@article{martin_chen_du_kumar_tevis_chang_pathak_thuo_2024, title={Atomic Reconstruction of Au Thin Films through Interfacial Strains}, volume={24}, ISSN={["1530-6992"]}, url={https://doi.org/10.1021/acs.nanolett.3c04412}, DOI={10.1021/acs.nanolett.3c04412}, abstractNote={Interfaces play a critical thermodynamic role in the existence of multilayer systems. Due to their utility in bridging energetic and compositional differences between distinct species, the formation of interfaces inherently creates internal strain in the bulk due to the reorganization needed to accommodate such a change. We report the effect of scaling interfacial stress by deposition of different adlayers on a host thin metal film. Intrinsic property differences between host and deposited metal atoms result in varying degree of composition and energy gradient within the interface. Interfacial stress can increase defects in the host leading to (i) energy dissipation and reorganization to minimize surface energy, and (ii) increased material strength. We infer that dissipation of interfacial stress induces defect migration, hence bulk and surface atomic reconstruction as captured by the surface roughness and grain size reduction coupled with a concomitant increase in material strength.}, number={6}, journal={NANO LETTERS}, author={Martin, Andrew and Chen, Jiahao and Du, Chuanshen and Kumar, Manish and Tevis, Ian D. and Chang, Boyce and Pathak, Sid and Thuo, Martin M.}, year={2024}, month={Jan}, pages={1967–1973} }
 @article{martin_pauls_chang_boyce_thuo_2024, title={Photo‐Activated Growth and Metastable Phase Transition in Metallic Solid Solutions}, url={https://doi.org/10.1002/adma.202309865}, DOI={10.1002/adma.202309865}, abstractNote={Laser processing in metals is versatile yet limited by its reliance in phase transformation through heating rather than electronic excitation due to their low absorptivity attributing from their highly ordered structures. Metastable states (i.e., surfaces, glasses, undercooled liquids), however, represent a unique platform, both energetically and structurally to enable energy landscape tuning through selective stimuli. Herein, we demonstrate this ansatz by exploiting thin passivating oxides to stabilize an undercooled state, followed by photo-perturbation of the near surface order to induce convective Marangoni flows, edge-coalescence and phase transition into a grown metastable solid bearing asymmetric composition between the near surface and core of the formed structure. The self-eliminating nature of the process creates a perfectly contained system which can maintain high relaxation energy barrier and deep metastable state for extended period of time. This article is protected by copyright. All rights reserved.}, journal={Advanced Materials}, author={Martin, Andrew and Pauls, Alana M. and Chang, Boyce and Boyce, Eva and Thuo, Martin}, year={2024}, month={Feb} }
 @article{martin_thuo_2024, title={Predicting Emergence of Nanoscale Order in Surface Oxides through Preferential Interactivity Parameter}, volume={18}, ISSN={["1936-086X"]}, url={https://doi.org/10.1021/acsnano.3c10935}, DOI={10.1021/acsnano.3c10935}, abstractNote={Diffusion and surface oxidation are critical processes in metal alloy designs and use. Surface oxides provide opportunities to improve material properties or performance beyond bulk alterations. Surface oxidation is, however, often oversimplified into a classical diffusion process. Passivating oxide surfaces are also thought to be lacking in complexity or critical information. A closer look, however, shows inherent complexity with kinetics-driven competition between the elements in the process leading to redox-speciation across a very small (nm) thickness. Questions that remain to be answered for a comprehensive understanding of surface oxides are diverse and call for interdisciplinary approaches. By using the thermodynamics-based Preferential Interactivity Parameter (PIP) alongside kinetic consideration, we show how complexity in these oxides can be predicted allowing us to tailor these thin films. We use our work, and that of others, to illustrate predictability while also highlighting that there is still much more to be done.}, number={9}, journal={ACS NANO}, author={Martin, Andrew and Thuo, Martin}, year={2024}, month={Feb}, pages={6740–6747} }
 @article{martin_thuo_2023, title={Beyond Hume-Rothery Rules}, volume={8}, ISSN={["2643-6728"]}, url={https://doi.org/10.1021/accountsmr.3c00126}, DOI={10.1021/accountsmr.3c00126}, abstractNote={ADVERTISEMENT RETURN TO ARTICLES ASAPPREVViewpointBeyond Hume-Rothery RulesAndrew MartinAndrew MartinDepartment of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United StatesMore by Andrew MartinView Biography and Martin Thuo*Martin ThuoDepartment of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States*Email: [email protected]More by Martin ThuoView Biographyhttps://orcid.org/0000-0003-3448-8027Cite this: Acc. Mater. Res. 2023, XXXX, XXX, XXX-XXXPublication Date (Web):August 18, 2023Publication History Received12 July 2023Published online18 August 2023https://doi.org/10.1021/accountsmr.3c00126© 2023 Accounts of Materials Research. Co-published by ShanghaiTech University and American Chemical Society. All rights reserved.Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views726Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (4 MB) Get e-AlertscloseSUBJECTS:Electrical energy,Energy landscapes,Free energy,Photovoltaics,Solutions Get e-Alerts}, journal={ACCOUNTS OF MATERIALS RESEARCH}, author={Martin, Andrew and Thuo, Martin}, year={2023}, month={Aug} }
 @article{du_gregory_jamadgni_pauls_chang_dorn_martin_foster_rossini_thuo_2023, title={Frontispiece: Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts}, url={https://doi.org/10.1002/anie.202384461}, DOI={10.1002/anie.202384461}, abstractNote={Carbon Materials. Spatially directed pyrolysis via thermally morphing surface adducts to create magnetic, paramagnetic, or oxide containing carbon fibers is reported by Martin Thuo et al. in their Research Article (e202308822).}, journal={Angewandte Chemie International Edition}, author={Du, Chuanshen and Gregory, Paul and Jamadgni, Dhanush U. and Pauls, Alana M. and Chang, Julia J. and Dorn, Rick W. and Martin, Andrew and Foster, E. Johan and Rossini, Aaron J. and Thuo, Martin}, year={2023}, month={Oct} }
 @article{du_gregory_jamadgni_pauls_chang_dorn_martin_foster_rossini_thuo_2023, title={Frontispiz: Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts}, url={https://doi.org/10.1002/ange.202384461}, DOI={10.1002/ange.202384461}, abstractNote={Carbon Materials. Spatially directed pyrolysis via thermally morphing surface adducts to create magnetic, paramagnetic, or oxide containing carbon fibers is reported by Martin Thuo et al. in their Research Article (e202308822).}, journal={Angewandte Chemie}, author={Du, Chuanshen and Gregory, Paul and Jamadgni, Dhanush U. and Pauls, Alana M. and Chang, Julia J. and Dorn, Rick W. and Martin, Andrew and Foster, E. Johan and Rossini, Aaron J. and Thuo, Martin}, year={2023}, month={Oct} }
 @article{foster_moreira_esfahani_zeidabadi_rostami_thuo_mohseni_2023, title={Iron oxide/graphenic carbon hybrid photocatalyst for decomposition of PFAS}, url={https://doi.org/10.21203/rs.3.rs-3438906/v1}, DOI={10.21203/rs.3.rs-3438906/v1}, abstractNote={Abstract In addressing the urgent global challenge posed by per- and polyfluoroalkyl substances (PFAS) contamination, a class of pollutants notorious for their persistence in aquatic ecosystems and human bloodstream, this research introduces a game-changing approach. Contrary to prevailing beliefs that effective PFAS degradation necessitates complex, cost-intensive methods, our study unveils a frugal, scalable iron oxide/graphenic carbon (Fe/g-C) hybrid photocatalyst synthesized with simplicity. Remarkably, this catalyst rapidly decomposes perfluorooctanoic acid (PFOA), achieving rates of ≥85% in just 3 hours at a UV fluence of 30.7 W cm -2 . Consistency in performance is further evidenced as the photocatalyst sustains decomposition rates of ≥85% over 30 hours under a UV fluence of 1.42±0.05 mW cm -2 . Not only does this work spotlight the potential of graphenic carbon-doped composites in tackling stubborn organic pollutants, but it also demonstrates a path to more efficient and practical PFAS degradation by reducing requisite UV fluence rates. This research serves as both an enlightening revelation and a promising solution to a pressing environmental concern.}, author={Foster, E. Johan and Moreira, Raphaell and Esfahani, Ehsan and Zeidabadi, Fatemeh and Rostami, Pani and Thuo, Martin and Mohseni, Madjid}, year={2023}, month={Nov} }
 @article{ward_thuo_soori_2023, title={One-dimensional hydrodynamic model for the isothermal-evaporation of an axisymmetric-unbounded liquid bridge}, volume={35}, ISSN={["1089-7666"]}, url={https://doi.org/10.1063/5.0175035}, DOI={10.1063/5.0175035}, abstractNote={In this manuscript, we examine the isothermal-evaporation of an unbounded axisymmetric liquid bridge confined between parallel-planar similar or chemically different substrates using both theory and experiments for axial Bond numbers 0.04 and 0.16. A perturbation analysis of the governing equations of motion produced a one-dimensional equation model, and this model made it possible to compute the interface profile evolution. Glass-acrylic or acrylic-acrylic substrate pairs (top-bottom) were used in experiments, with purified water as the liquid. Transient liquid-bridge volume estimates and contact angle data were extracted via image analysis at fixed time intervals and compared with results from the profiles that were computed using the one-dimensional equation model. There was good agreement when comparing the volume estimates and contact angle data.}, number={11}, journal={PHYSICS OF FLUIDS}, author={Ward, Thomas and Thuo, Martin and Soori, Tejaswi}, year={2023}, month={Nov} }
 @article{du_gregory_jamadgni_pauls_chang_dorn_martin_foster_rossini_thuo_2023, title={Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts}, volume={8}, ISSN={["1521-3773"]}, url={https://doi.org/10.1002/anie.202308822}, DOI={10.1002/anie.202308822}, abstractNote={Combustion is often difficult to spatially direct or tune associated kinetics - hence a run-away reaction. Coupling pyrolytic chemical transformation to mass transport and reaction rates (Damköhler number), however, we spatially directed ignition with concomitant switch from combustion to pyrolysis (low oxidant). This establishes a 'surface-then-core' order in ignition with concomitant change in burning rate. Herein, alkysilanes grafted onto cellulose fibers are pyrolyzed into non-flammable SiO2 terminating ignition propagation and further pyrolysis. Sustaining high temperatures, however, triggers ignition in the bulk of the fibers but under restricted gas flow (oxidant and/or waste) hence significantly reduced ignition propagation and pyrolysis compared the surface (Liñán's equation). This leads to inside-out degradation and, under felicitous choice of conditions, formation of graphitic tubes. Given the dependence on temperature, imbibing fibers with an exothermically oxidizing synthon (MnCl2) or a heat sink (KCl) abets or inhibits pyrolysis tuning tube-wall thickness. We apply this approach to create magnetic, paramagnetic, or oxide containing carbon fibers. The magnetic fibers are used for rapid filtration of oil from water.}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Du, Chuanshen and Gregory, Paul and Jamadgni, Dhanush U. and Pauls, Alana M. and Chang, Julia J. and Dorn, Rick W. and Martin, Andrew and Foster, E. Johan and Rossini, Aaron J. and Thuo, Martin}, year={2023}, month={Aug} }
 @article{du_gregory_jamadgni_pauls_chang_dorn_martin_foster_rossini_thuo_2023, title={Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts}, url={https://doi.org/10.1002/ange.202308822}, DOI={10.1002/ange.202308822}, abstractNote={Abstract Combustion is often difficult to spatially direct or tune associated kinetics—hence a run‐away reaction. Coupling pyrolytic chemical transformation to mass transport and reaction rates (Damköhler number), however, we spatially directed ignition with concomitant switch from combustion to pyrolysis (low oxidant). A ‘surface‐then‐core’ order in ignition, with concomitant change in burning rate,is therefore established. Herein, alkysilanes grafted onto cellulose fibers are pyrolyzed into non‐flammable SiO 2 terminating surface ignition propagation, hence stalling flame propagating. Sustaining high temperatures, however, triggers ignition in the bulk of the fibers but under restricted gas flow (oxidant and/or waste) hence significantly low rate of ignition propagation and pyrolysis compared to open flame (Liñán's equation). This leads to inside‐out thermal degradation and, with felicitous choice of conditions, formation of graphitic tubes. Given the temperature dependence, imbibing fibers with an exothermically oxidizing synthon (MnCl 2 ) or a heat sink (KCl) abets or inhibits pyrolysis leading to tuneable wall thickness. We apply this approach to create magnetic, paramagnetic, or oxide containing carbon fibers. Given the surface sensitivity, we illustrate fabrication of nm‐ and μm‐diameter tubes from appropriately sized fibers.}, journal={Angewandte Chemie}, author={Du, Chuanshen and Gregory, Paul and Jamadgni, Dhanush U. and Pauls, Alana M. and Chang, Julia J. and Dorn, Rick W. and Martin, Andrew and Foster, E. Johan and Rossini, Aaron J. and Thuo, Martin}, year={2023}, month={Oct} }
 @article{martin_chang_thuo_2022, title={Effect of Surface Nanostructures and Speciation on Undercooling for Low-Temperature Solder Alloys}, volume={5}, url={https://doi.org/10.1021/acsanm.1c03865}, DOI={10.1021/acsanm.1c03865}, abstractNote={Role of surface structure/composition in altering solidification behavior is demonstrated through undercooling of core–shell metal particles. Autonomous surface speciation in the passivating oxide plays a critical role in the relaxation of a molten metal due to divergence in the concentration and composition of oxidizing species across the thickness of the oxide layer. In an unreactive environment, surface speciation is dictated by flux, cohesive energy density, and surface energy minimization. Under oxidizing conditions (e.g., ambient), however, reduction potential, curvature, and surface plasticity dictate the spatial order and concentration(s) across thin passivating oxide layers. It is therefore important to redefine solubility beyond the limitations of Hume–Rothery rules by substituting electronegativity for redox potential and cohesive energy density. Increasing number of components in an alloy does not necessarily lead to increased undercooling, but a maximum is observed around two to three components. These results lead to an empirical observation that ΔGLS (Gibbs’ free energy for liquid–solid transition) around the freezing point can be understood from enthalpy and surface tension balance, with the degree of undercooling being a proportionality term for the enthalpic component. This work extends our understanding of classical nucleation theory by illustrating the importance of asymmetry in surface work in phase change, largely due to changes in structure of nanoscale passivating oxides. This phenomena is critical in development of low-temperature solders.}, number={3}, journal={ACS Applied Nano Materials}, publisher={American Chemical Society (ACS)}, author={Martin, Andrew and Chang, Boyce S. and Thuo, Martin}, year={2022}, month={Mar}, pages={3325–3332} }
 @article{du_wang_chen_martin_raturi_thuo_2022, title={Role of Nanoscale Roughness and Polarity in Odd–Even Effect of Self‐Assembled Monolayers}, url={https://doi.org/10.1002/anie.202205251}, DOI={10.1002/anie.202205251}, abstractNote={Abstract The dependency of substrate roughness on wetting properties of self‐assembled monolayers (SAMs) has been studied extensively, but most previous studies used limited selection of probing liquid and range of surface roughness. These studies disregarded the limit to observation of sub‐nanometer odd–even parity effect, hence are inconclusive. In this work we report the role of solvent polarity on the roughness‐dependency of wetting behavior of SAMs by studying static con‐tact angle of a variety of probing liquids, with different polarities, on SAMs formed on Ag‐based substrate with different surface morphology. By overlapping the roughness ranges with previous studies on Au, the limitation of surface roughness (RMS=1 nm) to observation of the odd–even effect using water as probing liquid was confirmed, but other probing liquid yielded different roughness‐dependent behaviors, with more polar solvent showing more roughness‐dependent behavior. Based on these observations, we concluded that there exists a phase‐transition like behavior in SAMs due to substrate roughness and molecule chain length, but whose determination is dependent on the probing liquid.}, journal={Angewandte Chemie International Edition}, author={Du, Chuanshen and Wang, Zhengjia and Chen, Jiahao and Martin, Andrew and Raturi, Dhruv and Thuo, Martin}, year={2022}, month={Jul} }
 @article{du_wang_chen_martin_raturi_thuo_2022, title={Role of Nanoscale Roughness and Polarity in Odd–Even Effect of Self‐Assembled Monolayers}, url={https://doi.org/10.1002/ange.202205251}, DOI={10.1002/ange.202205251}, abstractNote={Abstract The dependency of substrate roughness on wetting properties of self‐assembled monolayers (SAMs) has been studied extensively, but most previous studies used limited selection of probing liquid and range of surface roughness. These studies disregarded the limit to observation of sub‐nanometer odd–even parity effect, hence are inconclusive. In this work we report the role of solvent polarity on the roughness‐dependency of wetting behavior of SAMs by studying static con‐tact angle of a variety of probing liquids, with different polarities, on SAMs formed on Ag‐based substrate with different surface morphology. By overlapping the roughness ranges with previous studies on Au, the limitation of surface roughness (RMS=1 nm) to observation of the odd–even effect using water as probing liquid was confirmed, but other probing liquid yielded different roughness‐dependent behaviors, with more polar solvent showing more roughness‐dependent behavior. Based on these observations, we concluded that there exists a phase‐transition like behavior in SAMs due to substrate roughness and molecule chain length, but whose determination is dependent on the probing liquid.}, journal={Angewandte Chemie}, author={Du, Chuanshen and Wang, Zhengjia and Chen, Jiahao and Martin, Andrew and Raturi, Dhruv and Thuo, Martin}, year={2022}, month={Jul} }
 @article{thomas_chang_chang_thuo_rossini_2022, title={Solid-State Nuclear Magnetic Resonance Spectroscopy-Assisted Structure Determination of Coordination Polymers}, url={https://doi.org/10.1021/acs.chemmater.2c00593}, DOI={10.1021/acs.chemmater.2c00593}, abstractNote={The combination of advanced solid-state NMR spectroscopy, powder X-ray diffraction (PXRD), structure refinement, and quantum chemical calculations was used to determine the three-dimensional molecular structures of self-assembled, one-dimensional (1D) metal coordination polymers. The methodology is based on partial indexing of PXRD patterns followed by modeling using NMR constraints and, finally, Rietveld refinement and density functional theory (DFT) structure optimization. The protocol was first demonstrated on scandium acetate, a 1D coordination polymer with a known structure. The protocol was then applied to determine the crystal structures of nanocrystalline aluminum and gallium acetate hydroxide coordination polymers of unknown structures that were obtained by the etching of metallic nanoparticles in acidic solution. The PXRD and NMR-derived structures were validated by comparing the experimental and simulated PXRD patterns. Plane-wave DFT calculations confirm that the structures are energetically stable and that DFT-predicted NMR parameters are in reasonable agreement with the experimentally observed ones. The obtained molecular structures are in agreement with data from other characterization methods. The structure determination protocol demonstrated here should be applicable to analogous coordination polymers or porous framework materials.}, journal={Chemistry of Materials}, author={Thomas, Brijith and Chang, Boyce S. and Chang, Julia J. and Thuo, Martin and Rossini, Aaron J.}, year={2022}, month={Sep} }
 @article{du_andino_rotondaro_devlin_erramilli_ziegler_thuo_2022, title={Substrate Roughness and Tilt Angle Dependence of Sum-Frequency Generation Odd–Even Effects in Self-Assembled Monolayers}, volume={4}, url={https://doi.org/10.1021/acs.jpcc.2c01109}, DOI={10.1021/acs.jpcc.2c01109}, abstractNote={Role of substrate type, gold or silver, and surface roughness on the parity odd–even effect in n-alkanethiolate (n = 10–16) self-assembled monolayers (SAMs), materials of potential importance to molecular scale electronics, is studied using vibrational sum-frequency generation (SFG) spectroscopy. An inverted odd–even effect is observed for SAMs on Ag substrates relative to SAMs on Au. The metal-specific SFG spectra in the methyl and methylene stretching regions provide a sensitive probe of the in situ cant angle and molecular twist dependence of the interfacial group orientation. Within the precision of these measurements, disorder due to gauche defects is not evident in this spectral analysis. SFG methyl vibrational frequencies and line widths show parity and substrate dependence. Metal substrate roughness, an under-reported experimental parameter, affects the extent of odd–even methyl orientation anisotropy. Parity-dependent methyl orientation effects are seen on Ag beyond the roughness limit established by hydrophobicity data on Au. The SFG analysis predicts an ∼2.8 nm rms roughness limit for odd–even effects on Ag substrates. These SFG results further confirm the role competing pairwise short-range dispersive (∝1/r6) and longer range polar (∝1/r to 1/r4) interactions play in controlling the observed odd–even wetting behavior of SAMs on metal substrates as a function of surface roughness.}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society (ACS)}, author={Du, Chuanshen and Andino, Richard S. and Rotondaro, Matthew C. and Devlin, Shane W. and Erramilli, Shyamsunder and Ziegler, Lawrence D. and Thuo, Martin M.}, year={2022}, month={Apr} }
 @article{olson_blisko_du_liu_li_thurber_curtzwiler_ren_thuo_yong_et al._2021, title={Biobased superhydrophobic coating enabled by nanoparticle assembly}, volume={3}, url={https://doi.org/10.1039/D1NA00296A}, DOI={10.1039/D1NA00296A}, abstractNote={Understanding biobased nanocomposites is critical in fabricating high performing sustainable materials. In this study, fundamental nanoparticle assembly structures at the nanoscale are examined and correlated with the macroscale properties of coatings formulated with these structures. Nanoparticle assembly mechanisms within biobased polymer matrices were probed using in situ liquid-phase atomic force microscopy (AFM) and computational simulation. Furthermore, coatings formulated using these nanoparticle assemblies with biobased polymers were evaluated with regard to the hydrophobicity and adhesion after water immersion. Two biobased glycopolymers, hydroxyethyl cellulose (HEC) and hydroxyethyl starch (HES), were investigated. Their repeating units share the same chemical composition and only differ in monomer conformations (α- and β-anomeric glycosides). Unique fractal structures of silica nanoparticle assemblies were observed with HEC, while compact clusters were observed with HES. Simulation and AFM measurement suggest that strong attraction between silica surfaces in the HEC matrix induces diffusion-limited-aggregation, leading to large-scale, fractal assembly structures. By contrast, weak attraction in HES only produces reaction-limited-aggregation and small compact cluster structures. With high particle loading, the fractal structures in HEC formed a network, which enabled a waterborne formulation of superhydrophobic coating after silane treatment. The silica nanoparticle assembly in HEC was demonstrated to significantly improve adhesion, which showed minimum adhesion loss even after extended water immersion. The superior performance was only observed with HEC, not HES. The results bridge the assembly structures at the nanoscale, influenced by molecular conformation of biobased polymers, to the coating performance at the macroscopic level. Through this study we unveil new opportunities in economical and sustainable development of high-performance biobased materials.}, number={14}, journal={Nanoscale Advances}, publisher={Royal Society of Chemistry (RSC)}, author={Olson, Emily and Blisko, Jonathan and Du, Chuanshen and Liu, Yi and Li, Yifan and Thurber, Henry and Curtzwiler, Greg and Ren, Juan and Thuo, Martin and Yong, Xin and et al.}, year={2021}, pages={4037–4047} }
 @article{martin_chang_pauls_du_thuo_2021, title={Cover Picture: Stabilization of Undercooled Metals via Passivating Oxide Layers (Angew. Chem. Int. Ed. 11/2021)}, url={https://doi.org/10.1002/anie.202100679}, DOI={10.1002/anie.202100679}, abstractNote={Cool frustration. Engineering composition across a thin surface oxide layer of a metal particle, and stabilizing it with appropriate ligands, leads to a sharp surface stress that frustrates solidification. Chemical potential gradients from compositional variation and ligand inductive effects all contribute to stabilization of a metastable state. An undercooled liquid metal particle is formed, highlighting a new paradigm in engineering energy landscape of a material using thin surface layer, as described by Martin Thuo et al. in their Research Article on page 5928.}, journal={Angewandte Chemie International Edition}, author={Martin, Andrew and Chang, Boyce S. and Pauls, Alana M. and Du, Chuanshen and Thuo, Martin}, year={2021}, month={Mar} }
 @article{chang_du_pauls_thuo_2021, title={Frontispiece: Tunable Hydrophobicity via Dimensionally Confined Polymerization of Organometallic Adducts}, volume={60}, url={https://doi.org/10.1002/anie.202182562}, DOI={10.1002/anie.202182562}, abstractNote={Polymerization By restricting polymerization in native pores of undercooled particles, organometallic adducts were generated by Martin Thuo et al. in their Research Article on page 13929.}, number={25}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Chang, Julia J. and Du, Chuanshen and Pauls, Alana and Thuo, Martin}, year={2021}, month={Jun} }
 @article{chang_du_pauls_thuo_2021, title={Frontispiz: Tunable Hydrophobicity via Dimensionally Confined Polymerization of Organometallic Adducts}, volume={133}, url={https://doi.org/10.1002/ange.202182562}, DOI={10.1002/ange.202182562}, abstractNote={Polymerisation Im Forschungsartikel auf S. 14048 erzeugen Martin Thuo et al. metallorganische Addukte durch Einschränkung der Polymerisation in nativen Poren unterkühlter Partikel.}, number={25}, journal={Angewandte Chemie}, publisher={Wiley}, author={Chang, Julia J. and Du, Chuanshen and Pauls, Alana and Thuo, Martin}, year={2021}, month={Jun} }
 @inbook{thuo_gregory_banerjee_du_2021, place={Berlin, Boston}, title={Introduction: biopolymers and biocomposites}, url={http://dx.doi.org/10.1515/9781501521942-001}, DOI={10.1515/9781501521942-001}, abstractNote={Biopolymers and biocomposites are an exciting class of ubiquitous materials.Interest in these materials has been driven in part by their biocompatibility/biodegradability, sustainability, potentially low-cost, renewability, being environmental benign, among other properties.These fascinating materials come in a range of forms from the DNA and RNA that is essential to life to the cellulose and collagen that mechanically reinforce tissues and as hybrid organic-inorganic composites like teeth.Herein, we summarize some aspects of the two classes of materials biopolymer and biocomposites, exploring specific examples while pointing to potential monomer sources, neoteric postextraction modification and processing conditions.This lays the foundation to the following more specific chapters while illustrating the breadth of these material classes.}, booktitle={Biopolymers and Composites}, publisher={De Gruyter}, author={Thuo, Martin and Gregory, Paul and Banerjee, Souvik and Du, Chuanshen}, editor={Madbouly, S. and Zhang, C.Editors}, year={2021}, month={Sep}, pages={1–26} }
 @article{du_norris_thakur_chen_vanveller_thuo_2021, title={Molecular Conformation in Charge Tunneling across Large-Area Junctions}, volume={8}, url={https://doi.org/10.1021/jacs.1c06622}, DOI={10.1021/jacs.1c06622}, abstractNote={Self-assembled monolayers are predicated on thermodynamic equilibrium; hence, their properties project accessible relaxation pathways. Herein, we demonstrate that charge tunneling correlates with conformational degrees of freedom(s). Results from open chain and cyclic head groups show that, as expected, distribution in tunneling data correlates with the orientation of the head group, akin to the odd-even effect and more importantly the degree of conformational freedom, but fluctuates with applied bias. Trends in nature of distributions in current density illuminate the need for higher statistical moments in understanding these rather dynamic systems. We employ skewness, kurtosis, and estimation plots to show that the conformational degree of freedom in the head group significantly amplifies the odd-even effect and may lead to enhanced or perturbed tunneling based on whether the head group is on an odd- or even-parity spacer.}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Du, Chuanshen and Norris, Sean R. and Thakur, Abhishek and Chen, Jiahao and VanVeller, Brett and Thuo, Martin}, year={2021}, month={Sep} }
 @article{thomas_chang_thuo_rossini_2021, title={NMR-assisted structure determination of coordination polymers}, volume={77}, ISSN={2053-2733}, url={http://dx.doi.org/10.1107/s0108767321092175}, DOI={10.1107/s0108767321092175}, abstractNote={Structural analysis by XRD still remains a considerable challenge for materials that can’t be isolated as single crystals. In NMR crystallography structural constraints are extracted from the modern solid-state NMR techniques, and along with DFT (density functional theory) calculations.[1-4] NMR crystallography has been used to derive de novo structures and to aid the refinement of Xray powder diffraction data.[1-4] In this work, computational integration of advanced solid-state NMR with PXRD (powder X-ray diffraction) and modelling is used to understand the structure of metal coordination polymers that are produced by the etching of metal nanoparticles in acidic solution.[5-7] Notably, these coordination polymers have some structural disorder which gives rise to broadened diffraction peaks. Solid-state NMR was applied to determine the number of molecules in the asymmetric unit and give insight into the geometry at the metal center. Then, the PXRD pattern of the coordination polymers was partially indexed to find probable unit cells. The position of heavy atoms was then optimized within the unit cell using the Free Objects for Crystallography (FOX) software. Finally, Rietveld refinement and DFT optimization was used to obtain a final structural model. The final NMR and PXRD derived structure is validated by comparing the experimental and simulated PXRD pattern and NMR parameters. This protocol was verified on scandium acetate which has a known single crystal structure from the literature. The protocol was then successfully applied to microcrystalline gallium and aluminum coordination polymers. We anticipate that this methodology could be extended to similar kind of coordination polymers with inherent heterogeneous character.}, journal={Acta Crystallographica Section A Foundations and Advances}, publisher={International Union of Crystallography (IUCr)}, author={Thomas, Brijith and Chang, Boyce S. and Thuo, Martin and Rossini, Aaron}, year={2021}, month={Aug}, pages={C469} }
 @article{martin_chang_cutinho_shen_ward_cochran_thuo_2021, title={Passivation-driven speciation, dealloying and purification}, url={https://doi.org/10.1039/D0MH01832E}, DOI={10.1039/D0MH01832E}, abstractNote={Thin passivating surface oxide layers on metal alloys form a dissipation horizon between dissimilar phases, hence harbour an inherent free energy and composition gradient. We exploit this gradient to drive order and selective surface separation (speciation), enabling redox-driven enrichment of the core by selective conversion of low standard reduction potential (E°) components into oxides. Coupling this oxide growth to volumetric changes during solidification allows us to create oxide crystallites trapped in a metal ('ship-in-a-bottle') or extrusion of metal fingerlings on the heavily oxidized particle. We confirm the underlying mechanism through high temperature X-ray diffraction and characterization of solidification-trapped particle states. We demonstrate that engineering the passivating surface oxide can lead to purification via selective dealloying with concomitant enrichment of the core, leading to disparate particle morphologies.}, journal={Materials Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Martin, Andrew and Chang, Boyce and Cutinho, Joel and Shen, Liyang and Ward, Thomas and Cochran, Eric W. and Thuo, Martin M.}, year={2021} }
 @article{martin_chang_pauls_du_thuo_2021, title={Stabilization of Undercooled Metals via Passivating Oxide Layers}, volume={60}, url={https://doi.org/10.1002/anie.202013489}, DOI={10.1002/anie.202013489}, abstractNote={Advances in hybrid, high-density and flexible/wearable electronics demand low temperature metal processing. Undercooled metals have emerged as a solution to low temperature soldering and printing of conductive traces. The process of undercooling, however, relies on frustration of liquid-solid transition mainly through increase in activation energy by: i) elimination heterogeneous nucleants, or ii) frustrating homogeneous nucleation. We inferred that passivating oxide layers present an active platform that can isolate the core from heterogenous nucleants (physical barrier) while also raising the activation energy (thermodynamic/kinetic barrier) needed for solidification. The latter is due to composition gradients (speciation) that establishes a sharp chemical potential gradient across the thin (0.7-5 nm) oxide shell hence slows homogeneous nucleation. When this speciation is properly tuned, the oxide layer presents a previously unaccounted for interfacial tension in the overall energy landscape of the relaxing material. Herein, the role of surface oxide structure in enhancing and maintaining undercooling is demonstrated. We demonstrate that; i) the integrity of the passivation oxide is critical in stabilizing undercooled particle, a key tenet in developing heat-free solders, ii) that inductive effects play a critical role in undercooling, and iii) that magnitude of the effect of the passivating oxide can be larger that of size in undercooling.}, number={11}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Martin, Andrew and Chang, Boyce S. and Pauls, Alana M. and Du, Chuanshen and Thuo, Martin}, year={2021}, month={Mar}, pages={5928–5935} }
 @article{martin_chang_pauls_du_thuo_2021, title={Stabilization of Undercooled Metals via Passivating Oxide Layers}, volume={133}, url={https://doi.org/10.1002/ange.202013489}, DOI={10.1002/ange.202013489}, abstractNote={Abstract Undercooling metals relies on frustration of liquid–solid transition mainly by an increase in activation energy. Passivating oxide layers are a way to isolate the core from heterogenous nucleants (physical barrier) while also raising the activation energy (thermodynamic/kinetic barrier) needed for solidification. The latter is due to composition gradients (speciation) that establishes a sharp chemical potential gradient across the thin (0.7–5 nm) oxide shell, slowing homogeneous nucleation. When this speciation is properly tuned, the oxide layer presents a previously unaccounted for interfacial tension in the overall energy landscape of the relaxing material. We demonstrate that 1) the integrity of the passivation oxide is critical in stabilizing undercooled particle, a key tenet in developing heat‐free solders, 2) inductive effects play a critical role in undercooling, and 3) the magnitude of the influence of the passivating oxide can be larger than size effects in undercooling.}, number={11}, journal={Angewandte Chemie}, publisher={Wiley}, author={Martin, Andrew and Chang, Boyce S. and Pauls, Alana M. and Du, Chuanshen and Thuo, Martin}, year={2021}, month={Mar}, pages={5993–6000} }
 @article{kotov_liz-marzán_nie_thuo_zarzar_2021, title={The Endless and Turbulent Frontier of Academic Entrepreneurship}, url={https://doi.org/10.1021/acsnano.1c10031}, DOI={10.1021/acsnano.1c10031}, abstractNote={ADVERTISEMENT RETURN TO ISSUEEditorialNEXTThe Endless and Turbulent Frontier of Academic EntrepreneurshipNicholas A. KotovNicholas A. KotovDepartment of Materials Science and Engineering; Department of Chemical Engineering; Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, United StatesMore by Nicholas A. Kotovhttps://orcid.org/0000-0002-6864-5804, Luis M. Liz-MarzánLuis M. Liz-MarzánCIC biomaGUNE, Basque Research and Technology Alliance (BRTA); Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), 20014 Donostia-San Sebastián, SpainIKERBASQUE, Basque Foundation for Science, 48009 Bilbao, SpainMore by Luis M. Liz-Marzánhttps://orcid.org/0000-0002-6647-1353, Zhihong NieZhihong NieState Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University Shanghai 200433, P.R. ChinaMore by Zhihong Niehttps://orcid.org/0000-0001-9639-905X, Martin M. ThuoMartin M. ThuoDepartment of Materials Science and Engineering; Micro-Electronic Research Center; Biopolymer and Biocomposites Research Team, Center for Bioplastics and Biocomposites, Iowa State University, Ames, Iowa 50011, United StatesMore by Martin M. Thuohttps://orcid.org/0000-0003-3448-8027, and Lauren D. Zarzar*Lauren D. ZarzarDepartment of Chemistry and Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States*Email: [email protected]More by Lauren D. Zarzarhttps://orcid.org/0000-0002-3287-3602Cite this: ACS Nano 2021, 15, 11, 16947–16952Publication Date (Web):November 23, 2021Publication History Published online23 November 2021Published inissue 23 November 2021https://doi.org/10.1021/acsnano.1c10031Copyright © Published 2021 by American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1670Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (642 KB) Get e-AlertsSUBJECTS:Elements,Students,Environmental modeling,Energy,Materials Get e-Alerts}, journal={ACS Nano}, author={Kotov, Nicholas A. and Liz-Marzán, Luis M. and Nie, Zhihong and Thuo, Martin M. and Zarzar, Lauren D.}, year={2021}, month={Nov} }
 @article{martin_chang_pauls_du_thuo_2021, title={Titelbild: Stabilization of Undercooled Metals via Passivating Oxide Layers (Angew. Chem. 11/2021)}, volume={133}, url={https://doi.org/10.1002/ange.202100679}, DOI={10.1002/ange.202100679}, abstractNote={Kühle Frustration. Variieren der Zusammensetzung in einer dünnen Oberflächenoxidschicht eines Metallpartikels und deren Stabilisierung durch geeignete Liganden führen zu einer starken Oberflächenspannung, die die Erstarrung vereitelt. Chemische Potentialgradienten durch induktive Effekte der Liganden tragen zur Stabilisierung eines metastabilen Zustands bei. Es bildet sich ein unterkühltes flüssiges Metallteilchen, was ein neues Konzept für das gezielte Engineering der Energielandschaft eines Materials unter Verwendung einer dünnen Oberflächenschicht aufzeigt, wie Martin Thuo et al. in ihrem Forschungsartikel auf S. 5993 beschreiben. Kühle Frustration. Variieren der Zusammensetzung in einer dünnen Oberflächenoxidschicht eines Metallpartikels und deren Stabilisierung durch geeignete Liganden führen zu einer starken Oberflächenspannung, die die Erstarrung vereitelt. Chemische Potentialgradienten durch induktive Effekte der Liganden tragen zur Stabilisierung eines metastabilen Zustands bei. Es bildet sich ein unterkühltes flüssiges Metallteilchen, was ein neues Konzept für das gezielte Engineering der Energielandschaft eines Materials unter Verwendung einer dünnen Oberflächenschicht aufzeigt, wie Martin Thuo et al. in ihrem Forschungsartikel auf S. 5993 beschreiben. Duftstoffchemie Batterien Wasseroxidation Chemodynamische Therapie}, number={11}, journal={Angewandte Chemie}, publisher={Wiley}, author={Martin, Andrew and Chang, Boyce S. and Pauls, Alana M. and Du, Chuanshen and Thuo, Martin}, year={2021}, month={Mar}, pages={5633–5633} }
 @article{chang_du_pauls_thuo_2021, title={Tunable Hydrophobicity via Dimensionally Confined Polymerization of Organometallic Adducts}, volume={133}, url={https://doi.org/10.1002/ange.202101795}, DOI={10.1002/ange.202101795}, abstractNote={Abstract Fabrication of tunable fine textures on solid metal surfaces often demands sophisticated reaction/processing systems. By exploiting in situ polymerization and self‐assembly of inorganic adducts derived from liquid metals (the so‐called HetMet reaction) with concomitant solidification, solid metal films with tunable texture are readily fabricated. Serving as a natural dimensional confinement, interparticle pores and capillary‐adhered thin liquid films in a pre‐packed bed of undercooled liquid metal particles lead to the expeditious surface accumulation of organometallic synthons, which readily oligomerize and self‐assemble into concentration‐dictated morphologies/patterns. Tuning particle size, particle packing (flat or textured), and reactant concentration generates diverse, autonomously organized organometallic structures on a metal particle bed. Concomitant solidification and sintering of the underlying undercooled particle bed led to a multiscale patterned solid metal surface. The process is illustrated by creating tunable features on pre‐organized metal particle beds with concomitant tunable wettability as illustrated through the so‐called petal and lotus effects.}, number={25}, journal={Angewandte Chemie}, publisher={Wiley}, author={Chang, Julia J. and Du, Chuanshen and Pauls, Alana and Thuo, Martin}, year={2021}, month={Jun}, pages={14048–14055} }
 @article{chang_du_pauls_thuo_2021, title={Tunable Hydrophobicity via Dimensionally Confined Polymerization of Organometallic Adducts}, volume={60}, url={https://doi.org/10.1002/anie.202101795}, DOI={10.1002/anie.202101795}, abstractNote={Abstract Fabrication of tunable fine textures on solid metal surfaces often demands sophisticated reaction/processing systems. By exploiting in situ polymerization and self‐assembly of inorganic adducts derived from liquid metals (the so‐called HetMet reaction) with concomitant solidification, solid metal films with tunable texture are readily fabricated. Serving as a natural dimensional confinement, interparticle pores and capillary‐adhered thin liquid films in a pre‐packed bed of undercooled liquid metal particles lead to the expeditious surface accumulation of organometallic synthons, which readily oligomerize and self‐assemble into concentration‐dictated morphologies/patterns. Tuning particle size, particle packing (flat or textured), and reactant concentration generates diverse, autonomously organized organometallic structures on a metal particle bed. Concomitant solidification and sintering of the underlying undercooled particle bed led to a multiscale patterned solid metal surface. The process is illustrated by creating tunable features on pre‐organized metal particle beds with concomitant tunable wettability as illustrated through the so‐called petal and lotus effects.}, number={25}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Chang, Julia J. and Du, Chuanshen and Pauls, Alana and Thuo, Martin}, year={2021}, month={Jun}, pages={13929–13936} }
 @article{martin_kiarie_chang_thuo_2020, title={Chameleon Metals: Autonomous Nano‐Texturing and Composition Inversion on Liquid Metals Surfaces}, volume={132}, url={https://doi.org/10.1002/ange.201912639}, DOI={10.1002/ange.201912639}, abstractNote={Abstract Studies on passivating oxides on liquid metals are challenging, in part, due to plasticity, entropic, and technological limitations. In alloys, compositional complexity in the passivating oxide(s) and underlying metal interface exacerbates these challenges. This nanoscale complexity, however, offers an opportunity to engineer the surface of the liquid metal under felicitous choice of processing conditions. We inferred that difference in reactivity, coupled with inherent interface ordering, presages exploitable order and selectivity to autonomously present compositionally biased oxides on the surface of these metals. Besides compositional differences, sequential release of biased (enriched) components, via fractal‐like paths, allows for patterned layered surface structures. We, therefore, present a simple thermal‐oxidative compositional inversion (TOCI) method to introduce fractal‐like structures on the surface of these metals in a controlled (tier, composition, and structure) manner by exploiting underlying stochastic fracturing process. Using a ternary alloy, a three‐tiered (in structure and composition) surface structure is demonstrated.}, number={1}, journal={Angewandte Chemie}, publisher={Wiley}, author={Martin, Andrew and Kiarie, Winnie and Chang, Boyce and Thuo, Martin}, year={2020}, month={Jan}, pages={360–365} }
 @article{martin_du_chang_thuo_2020, title={Complexity and Opportunities in Liquid Metal Surface Oxides}, volume={32}, url={https://doi.org/10.1021/acs.chemmater.0c02047}, DOI={10.1021/acs.chemmater.0c02047}, abstractNote={The ability of metal alloys to rapidly oxidize in ambient condition presents both a challenge and an opportunity. Herein, we focus on opportunities buried in the passivating oxide of liquid metal p...}, number={21}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Martin, Andrew and Du, Chuanshen and Chang, Boyce and Thuo, Martin}, year={2020}, month={Nov}, pages={9045–9055} }
 @article{martin_kiarie_chang_thuo_2020, title={Cover Picture: Chameleon Metals: Autonomous Nano‐Texturing and Composition Inversion on Liquid Metals Surfaces (Angew. Chem. Int. Ed. 1/2020)}, volume={59}, url={https://doi.org/10.1002/anie.201914874}, DOI={10.1002/anie.201914874}, abstractNote={Chameleon Metals. Metal passivating oxide layers are complex pseudo-equilibrium systems with a plethora of undiscovered features. In their Research Article on page 352, M. Thuo et al. exploit the complexity of such a thin oxide layer to engineer surface design and structure, resulting in the formation of compositionally inverted surface features and nanoscale fractal-like designs. Chameleon Metals. Metal passivating oxide layers are complex pseudo-equilibrium systems with a plethora of undiscovered features. In their Research Article on page 352, M. Thuo et al. exploit the complexity of such a thin oxide layer to engineer surface design and structure, resulting in the formation of compositionally inverted surface features and nanoscale fractal-like designs. Electrocatalysis Protein Structures Asymmetric Catalysis Super-Resolution Imaging}, number={1}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Martin, Andrew and Kiarie, Winnie and Chang, Boyce and Thuo, Martin}, year={2020}, month={Jan}, pages={1–1} }
 @article{chang_martin_du_pauls_thuo_2020, title={Frontispiece: Heat‐Free Biomimetic Metal Molding on Soft Substrates}, url={https://doi.org/10.1002/anie.202083861}, DOI={10.1002/anie.202083861}, abstractNote={Soft Matter In their Communication on page 16346, M. Thuo et al. describe the development of a heat-free biomimetic metal patterning method. Rose-like structures were replicated using undercooled liquid metal core–shell particles.}, journal={Angewandte Chemie International Edition}, author={Chang, Julia J. and Martin, Andrew and Du, Chuanshen and Pauls, Alana M. and Thuo, Martin}, year={2020}, month={Sep} }
 @article{chang_martin_du_pauls_thuo_2020, title={Frontispiz: Heat‐Free Biomimetic Metal Molding on Soft Substrates}, url={https://doi.org/10.1002/ange.202083861}, DOI={10.1002/ange.202083861}, abstractNote={Weiche Materialien In der Zuschrift auf S. 16488 beschreiben M. Thuo et al. die Entwicklung einer biomimetischen Methode zur Musterbildung von Metallen. Rosenförmige Strukturen wurden unter Verwendung von unterkühlten flüssigmetallischen Kern-Schale-Partikeln repliziert.}, journal={Angewandte Chemie}, author={Chang, Julia J. and Martin, Andrew and Du, Chuanshen and Pauls, Alana M. and Thuo, Martin}, year={2020}, month={Sep} }
 @article{chang_martin_du_pauls_thuo_2020, title={Heat‐Free Biomimetic Metal Molding on Soft Substrates}, url={https://doi.org/10.1002/ange.202008621}, DOI={10.1002/ange.202008621}, abstractNote={Abstract Fabrication of bio‐templated metallic structures is limited by differences in properties, processing conditions, packing, and material state(s). Herein, by using undercooled metal particles, differences in modulus and processing temperatures can be overcome. Adoption of autonomous processes such as self‐filtration, capillary pressure, and evaporative concentration leads to enhanced packing, stabilization (jamming) and point sintering with phase change to create solid metal replicas of complex bio‐based features. Differentiation of subtle differences between cultivars of the rose flower with reproduction over large areas shows that this biomimetic metal patterning (BIOMAP) is a versatile method to replicate biological features either as positive or negative reliefs irrespective of the substrate. Using rose petal patterns, we illustrate the versatility of bio‐templated mapping with undercooled metal particles at ambient conditions, and with unprecedented efficiency for metal structures.}, journal={Angewandte Chemie}, author={Chang, Julia J. and Martin, Andrew and Du, Chuanshen and Pauls, Alana M. and Thuo, Martin}, year={2020}, month={Sep} }
 @article{chang_martin_du_pauls_thuo_2020, title={Heat‐Free Biomimetic Metal Molding on Soft Substrates}, volume={8}, url={https://doi.org/10.1002/anie.202008621}, DOI={10.1002/anie.202008621}, abstractNote={Fabrication of bio-templated metallic structures is limited by differences in properties, processing condition, packing, and material state. Herein, we demonstrate that using undercooled metal particles, differences in modulus and processing temperatures can be overcome. Similarly, adoption of autonomous processes like self-filtration, capillary pressure and evaporative concentration leads to enhanced packing, stabilization (jamming) and point sintering with phase change to create solid metal replicas of complex bio-based features. Differentiation of subtle differences between cultivars of the rose flower with reproduction over large areas shows that this BIOmimetic Metal Patterning (BIOMAP) is a versatile method to readily replicate biological features either as positive or negative reliefs irrespective of the substrate. Using rose petal patterns, we illustrate the versatility of bio-templated mapping with undercooled metal particles at ambient conditions, and with unprecedented efficiency for metal structures.}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Chang, Julia J. and Martin, Andrew and Du, Chuanshen and Pauls, Alana M. and Thuo, Martin}, year={2020}, month={Sep} }
 @article{martin_du_pauls_ward_thuo_2020, title={Polydispersity‐Driven Printing of Conformal Solid Metal Traces on Non‐Adhering Biological Surfaces}, url={https://doi.org/10.1002/admi.202001294}, DOI={10.1002/admi.202001294}, abstractNote={Metals and organics possess two very dissimilar surface energies, hence, do not naturally adhere to each other. This incompatibility is exacerbated by surface roughness yet advances in wearables and bioelectronics call for their integration. Mesoscale mechanical bonds, however, transcend the necessities of surface energy matching while taking advantage of surface texture. Herein, transient carrier fluids, particle size polydispersity, and capillary‐driven autonomous size‐sorting are exploited to conformally jam undercooled liquid metal particles on textured soft substrate. The well packed undercooled metal particles are then chemically activated to induce phase change, leading to a solid electrically conductive metal trace. Static and dynamic deposition of the particles is amenable to this surface‐templated printing of conductive traces. This process allows for printing across surfaces with varying surface features like on the brain, on paper (asymmetric porosity), or across smooth and rough brain sections. By tuning particle size and slurry concentration, good particle packing is demonstrated on a multi‐scale rough surface like a rose flower. This printing method is therefore compatible with delicate (low modulus), heat sensitive, and textured substrates hence compatible with biological tissues and organic substrates.}, journal={Advanced Materials Interfaces}, author={Martin, Andrew and Du, Chuanshen and Pauls, Alana M. and Ward, Thomas, III and Thuo, Martin}, year={2020}, month={Nov} }
 @article{chang_martin_thomas_li_dorn_gong_rossini_thuo_2020, title={Synthesis of Interface-Driven Tunable Bandgap Metal Oxides}, volume={2}, url={https://doi.org/10.1021/acsmaterialslett.0c00251}, DOI={10.1021/acsmaterialslett.0c00251}, abstractNote={Mixed bandgap and bandgap tunability in semiconductors is critical in expanding their use. Composition alterations through single-crystal epitaxial growth and formation of multi-layer tandem struct...}, number={9}, journal={ACS Materials Letters}, publisher={American Chemical Society (ACS)}, author={Chang, Boyce S. and Martin, Andrew and Thomas, Brijith and Li, Ang and Dorn, Rick W. and Gong, Jinlong and Rossini, Aaron J. and Thuo, Martin M.}, year={2020}, month={Sep}, pages={1211–1217} }
 @article{martin_kiarie_chang_thuo_2020, title={Titelbild: Chameleon Metals: Autonomous Nano‐Texturing and Composition Inversion on Liquid Metals Surfaces (Angew. Chem. 1/2020)}, volume={132}, url={https://doi.org/10.1002/ange.201914874}, DOI={10.1002/ange.201914874}, abstractNote={Chamäleon-Metalle. Die metallpassivierende Oxidschicht ist ein komplexes Pseudogleichgewichtssystem mit einer Vielzahl unentdeckter Merkmale. In ihrem Forschungsartikel auf S. 360 nutzen M. Thuo et al. die Komplexität dieser dünnen Oxidschicht für die gezielte Modifizierung von Oberflächendesign und -struktur, was in der Bildung von kompositorisch invertierten Oberflächenmerkmalen und nanoskaligen fraktalartigen Designs resultiert. Chamäleon-Metalle. Die metallpassivierende Oxidschicht ist ein komplexes Pseudogleichgewichtssystem mit einer Vielzahl unentdeckter Merkmale. In ihrem Forschungsartikel auf S. 360 nutzen M. Thuo et al. die Komplexität dieser dünnen Oxidschicht für die gezielte Modifizierung von Oberflächendesign und -struktur, was in der Bildung von kompositorisch invertierten Oberflächenmerkmalen und nanoskaligen fraktalartigen Designs resultiert. Elektrokatalyse Proteinstrukturen Asymmetrische Katalyse Hochauflösende Bildgebung}, number={1}, journal={Angewandte Chemie}, publisher={Wiley}, author={Martin, Andrew and Kiarie, Winnie and Chang, Boyce and Thuo, Martin}, year={2020}, month={Jan}, pages={1–1} }
 @article{chang_thomas_chen_tevis_karanja_çınar_venkatesh_rossini_thuo_2019, title={Ambient synthesis of nanomaterials by in situ heterogeneous metal/ligand reactions}, url={https://doi.org/10.1039/C9NR05448K}, DOI={10.1039/C9NR05448K}, abstractNote={Coordination polymers are ideal synthons in creating high aspect ratio nanostructures, however, conventional synthetic methods are often restricted to batch-wise and costly processes. Herein, we demonstrate a non-traditional, frugal approach to synthesize 1D coordination polymers by in situ etching of zerovalent metal particle precursors. This procedure is denoted as the heterogeneous metal/ligand reaction and was demonstrated on Group 13 metals as a proof of concept. Simple carboxylic acids supply the etchant protons and ligands for metal ions (conjugate base) in a 1 : 1 ratio. This scalable reaction produces a 1D polymer that assembles into high-aspect ratio 'nanobeams'. We demonstrate control over crystal structure and morphology by tuning the: (i) metal center, (ii) stoichiometry and (iii) structure of the ligands. This work presents a general scalable method for continuous, heat free and water-based coordination polymer synthesis.}, journal={Nanoscale}, publisher={Royal Society of Chemistry (RSC)}, author={Chang, Boyce S. and Thomas, Brijith and Chen, Jiahao and Tevis, Ian D. and Karanja, Paul and Çınar, Simge and Venkatesh, Amrit and Rossini, Aaron J. and Thuo, Martin M.}, year={2019} }
 @article{martin_kiarie_chang_thuo_2019, title={Chameleon Metals: Autonomous Nano‐Texturing and Composition Inversion on Liquid Metals Surfaces}, volume={59}, ISSN={1433-7851 1521-3773}, url={http://dx.doi.org/10.1002/anie.201912639}, DOI={10.1002/anie.201912639}, abstractNote={Studies on passivating oxides on liquid metals are challenging, in part, due to plasticity, entropic, and technological limitations. In alloys, compositional complexity in the passivating oxide(s) and underlying metal interface exacerbates these challenges. This nanoscale complexity, however, offers an opportunity to engineer the surface of the liquid metal under felicitous choice of processing conditions. We inferred that difference in reactivity, coupled with inherent interface ordering, presages exploitable order and selectivity to autonomously present compositionally biased oxides on the surface of these metals. Besides the compositional differences, sequential release of biased (enriched) components, via fractal-like paths, allows for patterned layered surface structures. We, therefore, present a simple thermal-oxidative compositional inversion (TOCI) method to introduce fractal-like structures on the surface of these metals in a controlled (tier, composition, and structure) manner by exploiting underlying stochastic fracturing process. Using a ternary alloy, a three-tiered (in structure and composition) surface structure is demonstrated.}, number={1}, journal={Angewandte Chemie International Edition}, publisher={Wiley}, author={Martin, Andrew and Kiarie, Winnie and Chang, Boyce and Thuo, Martin}, year={2019}, month={Dec}, pages={352–357} }
 @inproceedings{martin_chang_thuo_2019, title={Chemical Potential Driven Stabilization of Undercooled Particles}, booktitle={10th International Conference on Materials for Advanced Technologies (ICMAT 2019)}, author={Martin, A. and Chang, B. and Thuo, M.}, year={2019}, month={Jun} }
 @article{damon_maher_allen_baker_chang_maher_thuo_badu-tawiah_2019, title={Determining Surface Energy of Porous Substrates by Spray Ionization}, volume={35}, url={https://doi.org/10.1021/acs.langmuir.9b02419}, DOI={10.1021/acs.langmuir.9b02419}, abstractNote={We have developed a new spray-based method for characterizing surface energies of planar, porous substrates. Distinct spray modes (electrospray versus electrostatic-spray), from the porous substrates, occur in the presence of an applied DC potential after wetting with solvents of different surface tension. The ion current resulting from the spray process maximizes when the surface energy of the porous substrate approaches the surface tension of the wetting solvent. By monitoring selected ion current (e.g., benzoylecgonine, m/z 290→168) with a mass spectrometer or total ion current with an ammeter, the solvent surface tension yielding the maximum ion current was determined to indicate the surface energy of the solid. Detailed evaluations using polymeric substrates of known surface energies enabled effective calibration of the approach that resulted in the correct estimation of the surface energy of hydrophobic paper substrates prepared by gas-phase silanization. A three-parameter empirical model suggests that the experimentally observed ion current profile is governed by differential partitioning of analyte controlled by the interfacial forces between the wetting solvent and the porous substrate.}, number={43}, journal={Langmuir}, publisher={American Chemical Society (ACS)}, author={Damon, Deidre E. and Maher, Yosef S. and Allen, Danyelle M. and Baker, Jill and Chang, Boyce S. and Maher, Simon and Thuo, Martin M. and Badu-Tawiah, Abraham K.}, year={2019}, month={Oct}, pages={13853–13859} }
 @article{chang_boddupalli_boyer_orondo_bloch_bratlie_thuo_2019, title={Effect of surface morphologies and chemistry of paper on deposited collagen}, volume={484}, url={https://doi.org/10.1016/j.apsusc.2019.04.131}, DOI={10.1016/j.apsusc.2019.04.131}, abstractNote={Paper-based platforms for biological studies have received significant attention given that cellulose is ubiquitous, biocompatible, and can be readily organized into tunable fibrous structures. In the latter form, effect of complexity in surface morphologies (roughness, porosity and fiber organization) on cell-substrate interaction has not been thoroughly explored. We infer that altering the properties of a fibrous material should lead to significant changes in cellular microenvironment and direct the deposition of structurally analogous extracellular matrix (fiber-fiber templating) like collagen. Here, we elucidate the effect of varying paper roughness and surface chemistry on NIH/3T3 fibroblasts via organization of excreted collagen. Collagen intensity was found to increase linearly with paper porosity, indicating a 3D culture platform. The intensity, however, decays over time due to biodegradation of the substrate. Stability can be improved by introducing fluorinated alkyl silanes to yield hydrophobic paper. This process concomitantly transforms the substrate to a 2D-like scaffold where collagen is predominantly assembled on the surface, thus changing the cellular microenvironment. Altering surface energy also led to fluctuations in collagen intensity and organization over time for smooth (calendered) paper substrates. We infer that the increased roughness improves collagen adsorption through capillary driven petal effect. In general, the influence of the substrate simultaneously affects its ability to host collagen and guide orientation. These findings offer insights into the effects of secondary structures and chemistry of fibrous polymeric materials on cell culture, which we propose as vital parameters when using paper-based platforms.}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Chang, Boyce S. and Boddupalli, Anuraag and Boyer, Andrea F. and Orondo, Millicent and Bloch, Jean-Francis and Bratlie, Kaitlin M. and Thuo, Martin M.}, year={2019}, month={Aug}, pages={461–469} }
 @inproceedings{du_chen_martin_chang_wang_tevis_thuo_2019, title={Effect ofinterfacial stress on surface reconstruction in metal thin films}, booktitle={10th International Conference on Materials for Advanced Technologies (ICMAT 2019)}, author={Du, C. and Chen, J. and Martin, A. and Chang, B. and Wang, Z. and Tevis, I.D. and Thuo, M.}, year={2019}, month={Jun} }
 @inproceedings{chang_bratlie_bloch_thuo_2019, title={Frugal Innovations through surface and Interface engineering in Paper: Controlling Collagen organization}, booktitle={Tappi-Papercon Conference 2019}, author={Chang, B. and Bratlie, K. and Bloch, J.-F. and Thuo, M.}, year={2019} }
 @inproceedings{thuo_2019, title={Functional Materials through Surface and Interfaces}, booktitle={3M techforum}, author={Thuo, M.}, year={2019}, month={Sep} }
 @article{martin_chang_martin_paramanik_frankiewicz_kundu_tevis_thuo_2019, title={Heat‐Free Fabrication of Metallic Interconnects for Flexible/Wearable Devices}, url={https://doi.org/10.1002/adfm.201903687}, DOI={10.1002/adfm.201903687}, abstractNote={Exploiting interfacial excess (Γ), Laplace pressure jump (ΔP), surface work, and coupling them to surface reactivity have led to the synthesis of undercooled metal particles. Metastability is maintained by a core–shell particle architecture. Fracture of the thin shell leads to solidification with concomitant sintering. Applying Scherer's constitutive model for load‐driven viscous sintering on the undercooled particles implies that they can form conductive traces. Combining metastability to eliminate heat and robustness of viscous sintering, an array of conductive metallic traces can be prepared, leading to plethora of devices on various flexible and/or heat sensitive substrates. Besides mechanical sintering, chemical sintering can be performed, which negates the need of either heat or load. In the latter, connectivity is hypothesized to occur via a Frenkel's theory of sintering type mechanism. This work reports heat‐free, ambient fabrication of metallic conductive interconnects and traces on all types of substrates.}, journal={Advanced Functional Materials}, author={Martin, Andrew and Chang, Boyce S. and Martin, Zachariah and Paramanik, Dipak and Frankiewicz, Christophe and Kundu, Souvik and Tevis, Ian D. and Thuo, Martin}, year={2019}, month={Oct} }
 @inproceedings{bloch_chang_huber_passas_ando_thuo_carré_2019, title={Micro Characterization of z-resistance of papers}, booktitle={Tappi-Papercon Conference 2019}, author={Bloch, J.F. and Chang, B. and Huber, P. and Passas, R. and Ando, E. and Thuo, M. and Carré, B.}, year={2019} }
 @article{chang_fratzl_boyer_martin_ahrenholtz_moraes_bloch_dempsey_thuo_2019, title={Rapid Prototyping of Reconfigurable Microfluidic Channels in Undercooled Metal Particle-Elastomer Composites}, volume={58}, url={https://doi.org/10.1021/acs.iecr.8b06441}, DOI={10.1021/acs.iecr.8b06441}, abstractNote={Conventional fabrication of microfluidic channels/devices faces challenges such as single use channels, material incompartibility, and/or significant time consumption. We propose a flexible platfor...}, number={10}, journal={Industrial & Engineering Chemistry Research}, publisher={American Chemical Society (ACS)}, author={Chang, Boyce S. and Fratzl, Mario and Boyer, Andrea and Martin, Andrew and Ahrenholtz, Henry C. and Moraes, Isabelle De and Bloch, Jean-Francis and Dempsey, Nora M. and Thuo, Martin M.}, year={2019}, month={Mar}, pages={4137–4142} }
 @inproceedings{martin_chang_martin_paramanik_frankiewicz_kundu_tevis_thuo_2019, title={Undercooled Liquid Metal Particle Inks for Flexible Conductive Traces Using Direct Writing}, booktitle={10th International Conference on Materials for Advanced Technologies (ICMAT 2019)}, author={Martin, A. and Chang, B. and Martin, Z. and Paramanik, D. and Frankiewicz, C. and Kundu, S. and Tevis, I.D. and Thuo, M.}, year={2019}, month={Jun} }
 @inproceedings{du_norris_vanveller_thuo_2019, title={Understanding Molecular Conformation using Charge Tunneling Characteristics of Self-Assembled Monolayer (SAMs) Junctions}, booktitle={10th International Conference on Materials for Advanced Technologies (ICMAT 2019)}, author={Du, C. and Norris, S. and VanVeller, B. and Thuo, M.}, year={2019}, month={Jun} }
 @article{berda_deravi_foster_simon_thuo_2019, title={Virtual Issue: Next-Generation Smart Materials}, volume={52}, url={https://doi.org/10.1021/acs.macromol.9b01402}, DOI={10.1021/acs.macromol.9b01402}, abstractNote={I a particularly entertaining, engaging, and informative lecture on the topic of smart materials at the Gordon Research Conference on Polymers at Mount Holyoke College in 2013, Prof. Stuart Rowan suggested that the T1000, the liquid metal Sci-Fi villain from the movie “Terminator 2: Judgment Day”, represents the ultimate paradigm for any smart material: “It can change its shape, density, texture, color, modulus, rigidity, and toughness all on demand in response to multiple stimuli. It can also walk and talk! Now, that is a smart material!” Joking aside, this ethos that a true “smart material” should possess a suite of capabilities spanning a number of properties we normally ascribe to advanced materials and that imbuing new materials with such characteristics will require creative advances in synthetic polymer chemistry. This rationale provides the primary inspiration behind this Virtual Issue (VI) on Next-Generation Smart Materials. These selected publications highlight frontier efforts from experts across the globe in the synthesis and application of materials that can adapt and respond in a variety of ways to a variety of environmental conditions. The secondary inspiration for this VI is to call your attention to the 1st Workshop on NextGeneration Smart Materials, hosted by the ACS Division of Polymer Chemistry to be held in December 2019, in Savannah, Georgia. Much of the work chosen for this VI comes from laboratories of this workshop’s invited speaker list. If you find this collection of papers interesting, please consider joining us in Savannah to hear the most up-to-date advances while interfacing with some of the leading minds in this field. Foremost in our selection of highlighted papers is a Perspective Article on multistimuli, multiresponsive solidstate materials by Herbert co-workers (Figure 1). This is an}, number={17}, journal={Macromolecules}, publisher={American Chemical Society (ACS)}, author={Berda, Erik B. and Deravi, Leila F. and Foster, E. Johan and Simon, Yoan and Thuo, Martin M.}, year={2019}, month={Sep}, pages={6339–6341} }
 @article{chen_kundu_du_kadoma_giroux_thuo_2018, title={(Invited) Towards a Perfect Junction: Effect of Smoothening Electrodes on Tunneling Behaviors across Large Area Molecular Junctions}, url={https://doi.org/10.1149/08603.0079ecst}, DOI={10.1149/08603.0079ecst}, abstractNote={Eutectic gallium indium (EGaIn), as top electrode for self-assembled monolayers (SAMs) based tunneling junction, has recently received heightened attentions, in part, due to its ease of fabrication, high-yield working junctions, and reproducibility. Despite these advances, effect of sub-nanometer roughness inhibits delineation of second-order effects on tunneling characteristics that are inherent in the molecules or molecular assemblies. Some other effects, such as molecule/electrode interactions and field-dependent intra-molecular van der Waals interactions, can lead to new approaches of tuning charge transport properties. One challenge, however, is that junctions have inherent defects that can significantly skew interpretation of obtained results. Addition challenge is the decoupling of subtle molecular effects from vast number of measurements that usually give large distributions. To mitigate these challenges, we deployed a three-pronged approach entailing; i) tuning roughness of the bottom electrode at the angstrom scale, ii) polishing of the top-electrode, and iii) deploying statistical analysis to uncover interface effects. In this paper, the effect of these modifications on SAM and associated charge transport behavior will be discussed.}, journal={ECS Transactions}, author={Chen, Jiahao and Kundu, Souvik and Du, Chuasen and Kadoma, Atte and Giroux, Thomas and Thuo, Martin}, year={2018}, month={Jul} }
 @article{chen_kundu_du_kadoma_giroux_thuo_2018, title={(Invited) Towards a Perfect Junction: Effect of Smoothening Electrodes on Tunneling Behaviors across Large Area Molecular Junctions}, volume={MA2018-02}, url={https://doi.org/10.1149/MA2018-02/19/759}, DOI={10.1149/MA2018-02/19/759}, abstractNote={Large area self-assembled monolayers (SAMs) based tunneling junctions have recently received heightened attentions, in part, due to high yield of working junctions, ease of fabrication, and data reproducibility. Eutectic gallium indium (EGaIn) and ultra-flat metal substrate are used to form these molecular junctions. Despite the advances, effect of sub-nanometer roughness inhibits delineation of second-order effects on tunneling characteristics. These effects, like intra-molecular keesom interactions, can lead to new approaches to tuning charge transport behavior – a fete that is yet to be harnessed. To address this challenge, we deployed a three-pronged approach entailing; i) polishing of the top-electrode, ii) tuning roughness of the bottom electrode and the angstrom scale, and iii) deploying statistical analysis to uncover these effects. In this talk, effect of these modifications on SAM and associated charge transport behavior will be discussed.}, number={19}, journal={ECS Meeting Abstracts}, publisher={The Electrochemical Society}, author={Chen, Jiahao and Kundu, Souvik and Du, Chuasen and Kadoma, Atte and Giroux, Thomas and Thuo, Martin}, year={2018}, month={Jul}, pages={759–759} }
 @article{cutinho_chang_oyola-reynoso_chen_akhter_tevis_bello_martin_foster_thuo_2018, title={Autonomous Thermal-Oxidative Composition Inversion and Texture Tuning of Liquid Metal Surfaces}, volume={12}, url={https://doi.org/10.1021/acsnano.8b01438}, DOI={10.1021/acsnano.8b01438}, abstractNote={Droplets capture an environment-dictated equilibrium state of a liquid material. Equilibrium, however, often necessitates nanoscale interface organization, especially with formation of a passivating layer. Herein, we demonstrate that this kinetics-driven organization may predispose a material to autonomous thermal-oxidative composition inversion (TOCI) and texture reconfiguration under felicitous choice of trigger. We exploit inherent structural complexity, differential reactivity, and metastability of the ultrathin (∼0.7-3 nm) passivating oxide layer on eutectic gallium-indium (EGaIn, 75.5% Ga, 24.5% In w/w) core-shell particles to illustrate this approach to surface engineering. Two tiers of texture can be produced after ca. 15 min of heating, with the first evolution showing crumpling, while the second is a particulate growth above the first uniform texture. The formation of tier 1 texture occurs primarily because of diffusion-driven oxide buildup, which, as expected, increases stiffness of the oxide layer. The surface of this tier is rich in Ga, akin to the ambient formed passivating oxide. Tier 2 occurs at higher temperature because of thermally triggered fracture of the now thick and stiff oxide shell. This process leads to inversion in composition of the surface oxide due to higher In content on the tier 2 features. At higher temperatures (≥800 °C), significant changes in composition lead to solidification of the remaining material. Volume change upon oxidation and solidification leads to a hollow structure with a textured surface and faceted core. Controlled thermal treatment of liquid EGaIn therefore leads to tunable surface roughness, composition inversion, increased stiffness in the oxide shell, or a porous solid structure. We infer that this tunability is due to the structure of the passivating oxide layer that is driven by differences in reactivity of Ga and In and requisite enrichment of the less reactive component at the metal-oxide interface.}, number={5}, journal={ACS Nano}, publisher={American Chemical Society (ACS)}, author={Cutinho, Joel and Chang, Boyce S. and Oyola-Reynoso, Stephanie and Chen, Jiahao and Akhter, S. Sabrina and Tevis, Ian D. and Bello, Nelson J. and Martin, Andrew and Foster, Michelle C. and Thuo, Martin M.}, year={2018}, month={May}, pages={4744–4753} }
 @inproceedings{cutinho_chang_tevis_thuo_2018, title={Autonomous thermal-oxidative composition inversion (TOCI) and texture tuning in liquid metal particles}, booktitle={256th ACS National Meeting & Exposition}, author={Cutinho, J. and Chang, B. and Tevis, I. and Thuo, M.}, year={2018} }
 @inproceedings{martin_martin_paramanik_cinar_frankiewicz_tevis_thuo_2018, title={Conductive Materials Reliability in Flexible Electronics Symposium. Undercooled Liquid Metal Particle Inks for Flexible Conductive Traces Using Direct Writing}, booktitle={Materials Research Society (MRS) Fall Meeting}, author={Martin, Andrew and Martin, Zachariah and Paramanik, Dipak and Cinar, Simge and Frankiewicz, Christophe and Tevis, Ian D. and Thuo, Martin}, year={2018} }
 @article{damon_yin_allen_maher_tanny_oyola-reynoso_smith_maher_thuo_badu-tawiah_2018, title={Dried Blood Spheroids for Dry-State Room Temperature Stabilization of Microliter Blood Samples}, volume={90}, url={https://doi.org/10.1021/acs.analchem.8b01962}, DOI={10.1021/acs.analchem.8b01962}, abstractNote={It is well-known that 2D dried blood spots on paper offer a facile sample collection, storage, and transportation of blood. However, large volume requirements, possible analyte instability, and difficult sample recovery plague this method, lowering confidence in analyte quantification. For the first time, we demonstrate a new approach using 3D dried blood spheroids for stabilization of small volume blood samples, mitigating these effects without cold storage. Blood spheroids form on hydrophobic paper, preventing interaction between the sample and paper substrate, eliminating all chromatographic effects. Stability of the enzyme alanine transaminase and labile organic compounds such as cocaine and diazepam were also shown to increase in the spheroid by providing a critical radius of insulation. On-surface analysis of the dried blood spheroids using paper spray mass spectrometry resulted in sub-ng/mL limits of detection for all illicit drugs tested, representing 1 order of magnitude improvement compared with analysis from 2D dried blood spots.}, number={15}, journal={Analytical Chemistry}, publisher={American Chemical Society (ACS)}, author={Damon, Deidre E. and Yin, Mengzhen and Allen, Danyelle M. and Maher, Yosef S. and Tanny, Christian J. and Oyola-Reynoso, Stephanie and Smith, Barry L. and Maher, Simon and Thuo, Martin M. and Badu-Tawiah, Abraham K.}, year={2018}, month={Aug}, pages={9353–9358} }
 @article{kong_jin_thuo_song_joung_park_yoon_2018, title={Elucidating the Role of Molecule–Electrode Interfacial Defects in Charge Tunneling Characteristics of Large-Area Junctions}, volume={140}, url={https://doi.org/10.1021/jacs.8b08146}, DOI={10.1021/jacs.8b08146}, abstractNote={Interfacial chemistry at organic-inorganic contact critically determines the function of a wide range of molecular and organic electronic devices and other systems. The chemistry is, however, difficult to understand due to the lack of easily accessible in-operando spectroscopic techniques that permit access to interfacial structure on a molecular scale. Herein, we compare two analogous junctions formed with identical organic thin film and different liquid top-contacts (water droplet vs eutectic gallium indium alloy) and elucidate the puzzling interfacial characteristics. Specifically, we fine-tune the surface topography of the organic surface using mixed self-assembled monolayers (SAMs): single component SAM composed of rectifier (2,2'-bipyridyl-terminated n-undecanethiolate; denoted as SC11BIPY) is systematically diluted with nonrectifying n-alkanethiolates of different lengths (denoted as SC n where n = 8, 10, 12, 14, 16, 18). Characterization of the resulting mixed SAMs in wettability and tunneling currents with the two separate liquid top-contacts allows us to investigate the role of phase segregation and gauche defect in the SAM//liquid interfaces. The results reported here show the difference in length between SC11BIPY and SC n is translated into nanoscopic pits and gauche-conformer defects on the surface, and the difference in contact force-hydrostatic vs user pressures-and hence conformity of contact account for the difference in wettability and rectification behaviors. Our work provides an insight into the role of molecule-electrode interfacial defects in performance of molecular-scale electronic devices.}, number={38}, journal={Journal of the American Chemical Society}, publisher={American Chemical Society (ACS)}, author={Kong, Gyu Don and Jin, Junji and Thuo, Martin and Song, Hyunsun and Joung, Joonyoung F. and Park, Sungnam and Yoon, Hyo Jae}, year={2018}, month={Sep}, pages={12303–12307} }
 @article{gregory_martin_chang_oyola-reynoso_bloch_thuo_2018, title={Fabrication of Iron-Cellulose Microstructures through Thermal Degradation and Surface Functionalization}, volume={6}, journal={Frontiers in Chemistry}, author={Gregory, P.R. and Martin, A. and Chang, B.S. and Oyola-Reynoso, S. and Bloch, J.-F. and Thuo, M.M.}, year={2018}, pages={338} }
 @article{chang_martin_gregory_kundu_du_orondo_thuo_2018, title={Functional Materials through Surfaces and Interfaces}, volume={3}, ISSN={2059-8521}, url={http://dx.doi.org/10.1557/adv.2018.399}, DOI={10.1557/adv.2018.399}, abstractNote={In most materials, surfaces and interfaces present a significant portion of the workable area, but this area has often been erroneously perceived as a challenge in processing and thus, largely ignored. Surfaces and interfaces, however, present a network of energetically mismatched (sometimes metastable) molecules that can be exploited to either control surface reactions, engineer bulk stability or reveal new fundamental details of otherwise not well understood processes or systems as described herein. This perspective captures the role of i) structure, ii) chemistry and iii) thermodynamics at the interface in fabricating functional materials. Engineering substrate morphology enables tunable wettability either through the substrate or an adsorbed self-assembled monolayer (SAM), the latter being largely due to effect of sub-nanoscale roughness on conformational defects and overall order in the SAM. Surface roughness and chemistry also dictates the nature and amount of adventitious contaminants on a surface, and this was used to control volume of adsorbed water leading to controlled and tunable step-growth polymerization. The chemical treatment renders the paper amphiphobic, which could be used for self-cleaning surfaces and nucleation of water microdroplets for water harvesting. Finally, creating a self-passivating polished thin (∼0.7-2 nm) shell on a molten metal microdroplet kinetically frustrates solidification leading to significant undercooling. The ambient undercooled liquid metal is used for mechanically-triggered heat-free solder and smart composites. These three cases demonstrate key aspects of surface and interface engineering in integrating well-known concepts for the development of functional materials.}, number={37}, journal={MRS Advances}, publisher={Springer Science and Business Media LLC}, author={Chang, Boyce and Martin, Andrew and Gregory, Paul and Kundu, Souvik and Du, Chuanshen and Orondo, Millicent and Thuo, Martin}, year={2018}, month={Apr}, pages={2221–2233} }
 @inproceedings{chang_chen_tevis_oyola-reynoso_li_cinar_thomas_gong_rossini_thuo_2018, title={Infinite coordination polymers as intermediates in synthesis of 2D porous oxide from bulk metal}, booktitle={Gordon Research Conference: Crystal Engineering}, author={Chang, B. and Chen, J. and Tevis, I. and Oyola-Reynoso, S. and Li, A. and Cinar, S. and Thomas, B. and Gong, J. and Rossini, A. and Thuo, M.}, year={2018} }
 @inproceedings{kimani_fratzl_chang_kwasa_dempsey_ward_bloch_thuo_2018, title={Lab-on-paper: Designing paper-based diagnostic devices for translation and automation}, booktitle={256th ACS National Meeting & Exposition}, author={Kimani, F. and Fratzl, M. and Chang, B. and Kwasa, B. and Dempsey, N. and Ward, T. and Bloch, J.-F. and Thuo, M.}, year={2018} }
 @article{fratzl_chang_oyola-reynoso_blaire_delshadi_devillers_ward_dempsey_bloch_thuo_2018, title={Magnetic Two-Way Valves for Paper-Based Capillary-Driven Microfluidic Devices}, volume={3}, url={https://doi.org/10.1021/acsomega.7b01839}, DOI={10.1021/acsomega.7b01839}, abstractNote={This article presents a magnetically actuated two-way, three-position (+, 0, −), paper-based microfluidic valve that includes a neutral position (0)—the first of its kind. The system is highly robust, customizable, and fully automated. The advent of a neutral position and the ability to precisely control switching frequencies establish a new platform for highly controlled fluid flows in paper-based wicking microfluidic devices. The potential utility of these valves is demonstrated in automated, programmed, patterning of dyed liquids in a wicking device akin to a colorimetric assay but with a programmed fluid/reagent delivery. These valves are fabricated using facile methods and thus remain cost-effective for adoption into affordable point-of-care/bioanalytical devices.}, number={2}, journal={ACS Omega}, publisher={American Chemical Society (ACS)}, author={Fratzl, Mario and Chang, Boyce S. and Oyola-Reynoso, Stephanie and Blaire, Guillaume and Delshadi, Sarah and Devillers, Thibaut and Ward, Thomas, III and Dempsey, Nora M. and Bloch, Jean-Francis and Thuo, Martin M.}, year={2018}, month={Feb}, pages={2049–2057} }
 @article{chang_tutika_cutinho_oyola-reynoso_chen_bartlett_thuo_2018, title={Mechanically triggered composite stiffness tuning through thermodynamic relaxation (ST3R)}, url={https://doi.org/10.1039/C8MH00032H}, DOI={10.1039/C8MH00032H}, abstractNote={Recent developments in smart responsive composites have utilized various stimuli including heat, light, solvents, electricity, and magnetic fields to induce a change in material properties. Here, we report a thermodynamically driven mechanically responsive composite, exploiting irreversible phase-transformation (relaxation) of metastable undercooled liquid metal core shell particle fillers. Thermal and mechanical analysis reveals that as the composite is deformed, the particles transform from individual liquid droplets to a solid metal network, resulting in a 300% increase in Young's modulus. In contrast to previous phase change materials, this dramatic change in stiffness occurs autonomously under deformation, is insensitive to environmental conditions, and does not require external energy sources such as heat, light, or electricity. We demonstrate the utility of this approach by transforming a flat, flexible composite strip into a rigid, 3D structure that is capable of supporting 50× its own weight. The ability for shape change and reconfiguration are further highlighted, indicating potential for multiple pathways to trigger or tune composite stiffness.}, journal={Materials Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Chang, Boyce S. and Tutika, Ravi and Cutinho, Joel and Oyola-Reynoso, Stephanie and Chen, Jiahao and Bartlett, Michael D. and Thuo, Martin M.}, year={2018} }
 @article{chang_oyola‐reynoso_cutinho_thuo_2018, title={Rapid One‐Step Synthesis of Complex‐Architecture Block Polymers Using Inductively “Armed–Disarmed” Monomer Pairs}, url={https://doi.org/10.1002/marc.201800026}, DOI={10.1002/marc.201800026}, abstractNote={A facile method is reported for rapid, room-temperature synthesis of block copolymers (BCP) of complex morphology and hence nontraditional spherical assembly. The use of solvated electrons generates radical anions on olefinic monomers, and with a felicitous choice of monomer pairs, this species will propagate bimechanistically (via radical and the anion) to form BCPs. Molecular weight of the obtained BCP range from Mw = 97 000-404 000 g mol-1 (polydispersity index, PDI = 1.4-3.0) depending on monomer pairs. The composition of the blocks can be controlled by changing monomer ratio, with the caveat that yield is affected. Detailed characterization by 2D nuclear magnetic resonance spectroscopy, differential scanning calorimetry (DSC), and analysis of the mechanisms involved indicate the structure of obtained block copolymers to be at least a triblock with a complex central unit. Evaluating trends in the Hammett parameter segregates monomer pairs into "armed and disarmed" groups with respect to radical or anionic polymerization akin to oligosaccharides synthesis.}, journal={Macromolecular Rapid Communications}, author={Chang, Boyce S. and Oyola‐Reynoso, Stephanie and Cutinho, Joel and Thuo, Martin M.}, year={2018}, month={Apr} }
 @inproceedings{thuo_chang_2018, title={Rapid bimechanistic synthesis and self-assembly of block co- polymers using free electron initiators}, booktitle={256th ACS National Meeting & Exposition}, author={Thuo, M. and Chang, B.}, year={2018} }
 @inproceedings{chang_tutika_bartlett_thuo_2018, title={Stiffness Tunable (ST3R) Composite by Mechanical Actuation}, booktitle={Materials Research Society (MRS) Fall Meeting}, author={Chang, B. and Tutika, R. and Bartlett, M. and Thuo, M.}, year={2018} }
 @article{chen_kim_gathiaka_cho_kundu_yoon_thuo_2018, title={Understanding Keesom Interactions in Monolayer-Based Large-Area Tunneling Junctions}, volume={9}, url={https://doi.org/10.1021/acs.jpclett.8b01731}, DOI={10.1021/acs.jpclett.8b01731}, abstractNote={Charge transport across self-assembled monolayers (SAMs) has been widely studied. Discrepancies of charge tunneling data that arise from various studies, however, call for efforts to develop new statistical analytical approaches to understand charge tunneling across SAMs. Structure-property studies on charge tunneling across SAM-based junctions have largely been through comparison of average tunneling rates and associated variance. These early moments (especially the average) are dominated by barrier width-a static property of the junction. In this work, we show that analysis of higher statistical moments (skewness and kurtosis) reveals the dynamic nature of the tunnel junction. Intramolecular Keesom (dipole-dipole) interactions dynamically fluctuate with bias as dictated by stereoelectronic limitations. Analyzing variance in the distribution of tunneling data instead of the first statistical moment (average), for a series of n-alkanethiols containing internal amide and aromatic terminal groups, we observe that the direction of dipole moments affects molecule-electrode coupling. An applied bias induces changes in the tunneling probability, affecting the distribution of tunneling paths in large-area molecular junctions.}, number={17}, journal={The Journal of Physical Chemistry Letters}, publisher={American Chemical Society (ACS)}, author={Chen, Jiahao and Kim, Miso and Gathiaka, Symon and Cho, Soo Jin and Kundu, Souvik and Yoon, Hyo Jae and Thuo, Martin M.}, year={2018}, pages={5078–5085} }
 @article{chen_giroux_nguyen_kadoma_chang_vanveller_thuo_2018, title={Understanding interface (odd–even) effects in charge tunneling using a polished EGaIn electrode}, url={https://doi.org/10.1039/C7CP07531F}, DOI={10.1039/C7CP07531F}, abstractNote={Charge transport across large area molecular tunneling junctions is widely studied due to its potential in the development of quantum electronic devices. Large area junctions based on eutectic gallium indium (used in the form of a conical tip top electrode) have emerged as a reliable platform for delineating structure-property relationships. Discrepancies, however, arise from different tip-morphologies and fabrication techniques. It can be, therefore, challenging to make reliable conclusions based on molecular features. Of particular note is the discrepancy between the behaviors of hydrocarbons containing odd and even numbered carbons across different EGaIn electrodes. Moreover, inconsistencies in tip roughness and oxide thickness can lead to more than a 100× increase in current densities with narrow distribution in data. Besides effects on the precision vs. accuracy of data, a theoretically predicted length-dependent limit to observation of the odd-even effect has not been realized experimentally. We developed a method to chemically polish the EGaIn tip to allow formation of smooth conformal contact due to re-establishment of liquid character at the point of contact though tension-driven reconstruction of a thin oxide layer. To evaluate the polished tip, we measured charge transport behavior across n-alkanethiolate SAMs and observed good correlation in the odd-even oscillation behavior to that observed from wetting studies. Since these molecules are homologues of each other, only differing in the orientation of the terminal CH2CH3 moiety, the odd-even effects are governed by orientation induced differences in the absences of SAM (gauche) defects. Comparison of obtained data with the literature shows significant difference between odd-numbered SAMs across Ag and Au.}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Chen, Jiahao and Giroux, Thomas J. and Nguyen, Yen and Kadoma, Atte A. and Chang, Boyce S. and VanVeller, Brett and Thuo, Martin M.}, year={2018} }
 @inproceedings{thuo_2017, place={Cambridge, MA}, title={Frugal Innovation in Polymer Engineer Training}, booktitle={8th North America Symposium on Materials Education Symposium}, author={Thuo, M.}, year={2017}, month={Aug} }
 @inproceedings{thuo_2017, title={Frugal Innovation in Polymer Engineers Training}, booktitle={8th North America Materials Education Symposium}, author={Thuo, M.}, year={2017} }
 @inproceedings{thuo_2017, title={Frugal innovation: Synthesis and applications of undercooled metal particles}, booktitle={Basic Research in Colloids, Surfactants & Nanomaterials, Division of Colloid and Surface Chemistry, ACS national meeting}, author={Thuo, M.}, year={2017} }
 @inproceedings{thuo_2017, title={Interfacial stress induced metal thin film surface reorganization}, booktitle={Deposition & Etching of Nanostructures, Division of Colloid and Surface Chemistry, ACS national meeting}, author={Thuo, M.}, year={2017} }
 @inproceedings{fratzl_chang_oyola-reynoso_blaire_delshadia_devillers_cugat_dempsey_thuo_bloch_2017, title={Magnet-paper composites for low-cost two-way valves and other active structures in -pads}, booktitle={MicroTAS 2017}, author={Fratzl, M. and Chang, B. and Oyola-Reynoso, S. and Blaire, G. and Delshadia, S. and Devillers, T. and Cugat, O. and Dempsey, N.M. and Thuo, M. and Bloch, J.-F.}, year={2017}, month={Oct} }
 @article{oyola-reynoso_frankiewicz_chang_chen_bloch_thuo_2017, title={Paper-based microfluidic devices by asymmetric calendaring}, volume={11}, url={https://doi.org/10.1063/1.4974013}, DOI={10.1063/1.4974013}, abstractNote={We report a simple, efficient, one-step, affordable method to produce open-channel paper-based microfluidic channels. One surface of a sheet of paper is selectively calendared, with concomitant hydrophobization, to create the microfluidic channel. Our method involves asymmetric mechanical modification of a paper surface using a rolling ball (ball-point pen) under a controlled amount of applied stress (σz) to ascertain that only one side is modified. A lubricating solvent (hexane) aids in the selective deformation. The lubricant also serves as a carrier for a perfluoroalkyl trichlorosilane allowing the channel to be made hydrophobic as it is formed. For brevity and clarity, we abbreviated this method as TACH (Targeted Asymmetric Calendaring and Hydrophobization). We demonstrate that TACH can be used to reliably produce channels of variable widths (size of the ball) and depths (number of passes), without affecting the nonworking surface of the paper. Using tomography, we demonstrate that these channels can vary from 10s to 100s of microns in diameter. The created hydrophobic barrier extends around the channel through wicking to ensure no leakages. We demonstrate, through modeling and fabrication, that flow properties of the resulting channels are analogous to conventional devices and are tunable based on associated dimensionless numbers.}, number={1}, journal={Biomicrofluidics}, publisher={AIP Publishing}, author={Oyola-Reynoso, S. and Frankiewicz, C. and Chang, B. and Chen, J. and Bloch, J.-F. and Thuo, M. M.}, year={2017}, month={Jan}, pages={014104} }
 @article{chen_wang_oyola-reynoso_thuo_2017, title={Properties of Self-Assembled Monolayers Revealed via Inverse Tensiometry}, volume={33}, url={https://doi.org/10.1021/acs.langmuir.7b01937}, DOI={10.1021/acs.langmuir.7b01937}, abstractNote={Self-assembled monolayers (SAMs) have emerged as a simple platform technology and hence have been broadly studied. With advances in state-of-the-art fabrication and characterization methods, new insights into SAM structure and related properties have been delineated, albeit with some discrepancies and/or incoherencies. Some discrepancies, especially between experimental and theoretical work, are in part due to the misunderstanding of subtle structural features such as phase evolution and SAM quality. Recent work has, however, shown that simple techniques, such as the measurement of static contact angles, can be used to delineate otherwise complex properties of the SAM, especially when complemented by other more advanced techniques. In this article, we highlight the effect of nanoscale substrate asperities and molecular chain length on the SAM structure and associated properties. First, surfaces with tunable roughness are prepared on both Au and Ag, and their corresponding n-alkanethiolate SAMs are characterized through wetting and spectroscopy. From these data, chain-length- and substrate-morphology-dependent limits to the odd-even effect (structure and properties vary with the number of carbons in the molecules and the nature of the substrate), parametrization of gauche defect densities, and structural phase evolution (liquidlike, waxy, crystalline interfaces) are deduced. An evaluation of the correlation between the effect of roughness and the components of surface tension (polar-γp and dispersive-γd) reveals that wetting, at nanoscale rough surfaces, evolves proportionally with the ratio of the two components of surface tension. The evolution of conformational order is captured over a range of molecular lengths and parametrized through a dimensionless number, χc. By deploying a well-known tensiometry technique (herein the liquid is used to characterize the solid, hence the term inverse tensiometry) to characterize SAMs, we demonstrate that complex molecular-level phenomena in SAMs can be understood through simplicity.}, number={47}, journal={Langmuir}, publisher={American Chemical Society (ACS)}, author={Chen, Jiahao and Wang, Zhengjia and Oyola-Reynoso, Stephanie and Thuo, Martin M.}, year={2017}, month={Nov}, pages={13451–13467} }
 @article{chen_chang_oyola-reynoso_wang_thuo_2017, title={Quantifying Gauche Defects and Phase Evolution in Self-Assembled Monolayers through Sessile Drops}, volume={2}, url={https://doi.org/10.1021/acsomega.7b00355}, DOI={10.1021/acsomega.7b00355}, abstractNote={Self-assembled monolayers (SAMs) are widely used in surface modifications, specifically in tuning the surface chemistry of materials. The structure and properties of SAMs have been extensively studied often with sophisticated tools, even for the simplest n-alkanethiolate SAMs. In SAMs, especially in linear n-alkanethiolates, the properties are dependent on the chain length, which is best manifested in the so-called odd–even effect, a simple yet not fully understood phenomenon. One main challenge is fully delineating the origin of length-dependent properties, which can be due to the structure (ideal SAMs), defect evolution, or substrate-molecule effects. This study demonstrates that utilizing the wetting behavior of polar (water) and nonpolar (hexadecane (HD)) solvents on n-alkanethiolate SAMs formed on ultraflat gold and silver surfaces, the evolution of chain-length-dependent gauche defects can be revealed and parameterized through a newly defined dimensionless number (χ). The observation of the odd–even effect in hydrophobicity, however, depends on the thiol chain length, and it was only observed on longer-chain (>C8) molecules. The trend in this odd–even effect demonstrates that there are three main transitions in the nature of wetting, hence structure, across n-alkanethiols. From wetting with HD, the role of dispersive components in wetting reveal that the SAMs are dynamic, which we attribute to rotations associated with previously reported evolution in gauche defects and changes in packing density. Therefore, from re-expression of the Young–Dupre equation, we define a new dimensionless number associated with molecular conformations, whose periodicity mirrors the energetics of Goodman’s conformations of n-alkanes in unbound states and associated four- or two-twist turns. Therefore, we infer that the evolution in surface energy is largely due to molecular conformations and associated relaxations of the bound thiolates.}, number={5}, journal={ACS Omega}, publisher={American Chemical Society (ACS)}, author={Chen, Jiahao and Chang, Boyce and Oyola-Reynoso, Stephanie and Wang, Zhengjia and Thuo, Martin}, year={2017}, month={May}, pages={2072–2084} }
 @inproceedings{thuo_2017, title={Rapid free-electron initiated selective polymerization at room temperature}, booktitle={General Topics: New Synthesis & Characterization of Polymers, Division of Polymer Chemistry, ACS national meeting}, author={Thuo, M.}, year={2017} }
 @inproceedings{thuo_2017, title={Recruiting physisorbed water for green and bio-degradable perfluorinated surface modifications}, booktitle={General Papers/New Concepts in Polymeric Materials, Division of Polymeric Materials Science and Engineering, ACS national meeting}, author={Thuo, M.}, year={2017} }
 @article{kimani_mwangi_kwasa_kusow_ngugi_chen_liu_cademartiri_thuo_2017, title={Rethinking the Design of Low-Cost Point-of-Care Diagnostic Devices}, volume={8}, ISSN={2072-666X}, url={http://dx.doi.org/10.3390/mi8110317}, DOI={10.3390/mi8110317}, abstractNote={Reducing the global diseases burden requires effective diagnosis and treatment. In the developing world, accurate diagnosis can be the most expensive and time-consuming aspect of health care. Healthcare cost can, however, be reduced by use of affordable rapid diagnostic tests (RDTs). In the developed world, low-cost RDTs are being developed in many research laboratories; however, they are not being equally adopted in the developing countries. This disconnect points to a gap in the design philosophy, where parameterization of design variables ignores the most critical component of the system, the point-of-use stakeholders (e.g., doctors, nurses and patients). Herein, we demonstrated that a general focus on reducing cost (i.e., “low-cost”), rather than efficiency and reliability is misguided by the assumption that poverty reduces the value individuals place on their well-being. A case study of clinicians in Kenya showed that “zero-cost” is a low-weight parameter for point-of-use stakeholders, while reliability and standardization are crucial. We therefore argue that a user-driven, value-addition systems-engineering approach is needed for the design of RDTs to enhance adoption and translation into the field.}, number={11}, journal={Micromachines}, publisher={MDPI AG}, author={Kimani, Faith and Mwangi, Samuel and Kwasa, Benjamin and Kusow, Abdi and Ngugi, Benjamin and Chen, Jiahao and Liu, Xinyu and Cademartiri, Rebecca and Thuo, Martin}, year={2017}, month={Oct}, pages={317} }
 @inproceedings{thuo_2017, title={Revisiting the structure-properties relation in charge transport across large areamolecular tunneling junctions}, booktitle={Multicenter Molecules & Coupled Molecular Assemblies: Synthesis, Characterization & Theory, Division of Physical Chemistry, ACS national meeting}, author={Thuo, M.}, year={2017}, month={Apr} }
 @article{chen_gathiaka_wang_thuo_2017, title={Role of Molecular Dipoles in Charge Transport across Large Area Molecular Junctions Delineated Using Isomorphic Self-Assembled Monolayers}, volume={121}, url={https://doi.org/10.1021/acs.jpcc.7b07634}, DOI={10.1021/acs.jpcc.7b07634}, abstractNote={Delineating the role of dipoles in large area junctions that are based on self-assembled monolayers (SAMs) is challenging due to molecular tilt, surface defects, and interchain coupling among other features. To mitigate SAM-based effects in study of dipoles, we investigated tunneling rates across carboranes—isostructural molecules that orient along the surface normal on Au (but bear different dipole moments) without changing the thickness, packing density, or morphology of the SAM. Using the Au-SAM//Ga2O3-EGaIn junction (where “//” = physisorption, “–” = chemisorption, and EGaIn is eutectic gallium–indium), we observe that molecules with dipole moments oriented along the surface normal (with dipole moment, p = 4.1D for both M9 and 1O2) gave lower currents than when the dipole is orthogonal (p = 1.1 D, M1) at ±0.5 V applied bias. Similarly, from transition voltage spectroscopy, the transition voltages, VT (volt), are significantly different. (0.5, 0.43, and 0.4 V for M1, M9, and 1O2, respectively). We infe...}, number={43}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society (ACS)}, author={Chen, Jiahao and Gathiaka, Symon and Wang, Zhengjia and Thuo, Martin}, year={2017}, month={Nov}, pages={23931–23938} }
 @inproceedings{thuo_2017, title={Self-assembled coordination polymer as inter-mediate in synthesis of porous oxide from bulk metal}, booktitle={Chemistry of Materials: Metal Organic Frameworks, Division of Inorganic Chemistry, ACS national meeting}, author={Thuo, M.}, year={2017} }
 @inproceedings{thuo_2017, place={Singapore}, title={Simplicity: Exploiting Wetting in Self-Assembled Monolayers to Understand Charge Transport}, booktitle={9th International Conference on Materials for Advanced Technologies (ICMAT}, author={Thuo, M.}, year={2017} }
 @article{chang_oyola-reynoso_chen_lu_thuo_2017, title={Solvated-electron initiated rapid polymerization at ambient-temperature: a case of monomer solubility}, volume={8}, url={https://doi.org/10.1039/C7PY00416H}, DOI={10.1039/C7PY00416H}, abstractNote={Solvated electrons are highly reactive species that offer a chance to develop odd-numbered electron chemistry in the form of a radical (1 electron) or a radical-anion (3 electrons). Although discovered more than half a century ago, their utility is encumbered by misunderstandings in monomer selectivity and inconsistencies in the polymerization mechanism. In this article, disagreements in the literature are re-examined, and through felicitous choice of reaction conditions (room temperature, partial monomer solubility, separation of reaction from undissolved metal), new insights were drawn from the polymerization of styrene and acrylate monomers. We observe that rapid polymerization gives polymers with significantly high molecular weights (Mw > 104 g mol−1, PDI < 2) in less than a minute. We note that negative inductive effects on an olefinic monomer are essential for polymerization, with olefins bearing unsubstituted hydrocarbons (positive inductive effects) failing to polymerize at all. We also demonstrate co-polymerization of styrene and methyl methacrylate, albeit with a significant bias towards the latter. We infer that the first species formed by electron transfer is a radical anion; however, the survival of the free radicals depends on the rate of de-solvation. Dimerization of the radical anions is promoted by a high local concentration of the initiated monomer. This process is highly dependent on enthalpy–entropy relations during the reaction–desolvation process, which we expound on using solubility and Hammett parameters.}, number={22}, journal={Polymer Chemistry}, publisher={Royal Society of Chemistry (RSC)}, author={Chang, Boyce S. and Oyola-Reynoso, Stephanie and Chen, Jiahao and Lu, Mingchang and Thuo, Martin M.}, year={2017}, pages={3475–3484} }
 @article{chen_liu_tevis_andino_miller_ziegler_chen_thuo_2017, title={Spectroscopic evidence for the origin of odd–even effects in self-assembled monolayers and effects of substrate roughness}, volume={19}, url={https://doi.org/10.1039/C6CP07580K}, DOI={10.1039/C6CP07580K}, abstractNote={This paper reports the effects of substrate roughness on the odd-even effect in n-alkanethiolate self-assembled monolayers (SAMs) probed by vibrational sum frequency generation (SFG) spectroscopy. By fabricating SAMs on surfaces across the so-called odd-even limit, we demonstrate that differentiation of the vibrational frequencies of CH3 from SAMs derived from alkyl thiols with either odd (SAMO) or even (SAME) numbers of carbons depends on the roughness of the substrate on which they are formed. Odd-even oscillation in SFG susceptibility amplitudes was observed for spectra derived from SAME and SAMO fabricated on flat surfaces (RMS roughness = 0.4 nm) but not on rougher surfaces (RMS roughness = 2.38 nm). In addition, we discovered that local chemical environments for the terminal CH3 group have a chain-length dependence. There seems to be a transition at around C13, beyond which SAMs become "solid-like".}, number={10}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Chen, Jiahao and Liu, Jian and Tevis, Ian D. and Andino, Richard S. and Miller, Christina M. and Ziegler, Lawrence D. and Chen, Xin and Thuo, Martin M.}, year={2017}, pages={6989–6995} }
 @inproceedings{thuo_2017, place={Singapore}, title={Statistical Tools to Reveal Effect of Dipole Moments in Charge Transport}, booktitle={9th International Conference on Materials for Advanced Technologies (ICMAT}, author={Thuo, M.}, year={2017} }
 @article{sodhi_brodersen_cademartiri_thuo_nijhuis_2017, title={Surface and buried interface layer studies on challenging structures as studied by ARXPS}, volume={49}, ISSN={0142-2421 1096-9918}, url={http://dx.doi.org/10.1002/sia.6270}, DOI={10.1002/sia.6270}, abstractNote={Previous extensive studies were performed at Surface Science Western on the treatment of III‐V semiconductors to produce surfaces suitable for subsequent epitaxial growth. X‐ray photoelectron spectroscopy (XPS) was used to study oxide formation and capping techniques, and to monitor changes that would occur upon thermal desorption. The effects of a remote plasma on these surfaces were studied as well as to apply thin dielectric films of Si3N4 in order to study interfacial properties. Angle‐resolved XPS (ARXPS) was performed in many cases to ascertain oxide layer thickness, uniformity, and structure. For the types of surfaces studied—mirror finished semiconductors, ARXPS is straightforward, and the angular dependence is obtained by physically altering the surface orientation with respect to the analyser. While the sample can be repositioned with care to analyse the same spot, changing the angle will effectively change the sampling area, further, surface topography can preclude the use of ARXPS. Use of parallel PARXPS, now available on recent instrumentation, can alleviate these problems. In this case, photoelectrons are collected simultaneously from a large angle. A multichannel detector allows this to be split into smaller angles thereby giving the PARXPS spectra without physically tilting the sample. Further, because the sample is not tilted, topographical effects are minimised allowing meaningful data to be extracted from not so perfect samples. To illustrate this, a detailed PARXPS study on a gallium Indium eutectic (EGaIn) will be presented. Various methods of extracting the depth information from these spectra will be discussed. Finally, the application of using PARXPS to study buried interfaces will be briefly discussed. Copyright © 2017 John Wiley & Sons, Ltd.}, number={13}, journal={Surface and Interface Analysis}, publisher={Wiley}, author={Sodhi, Rana N. S. and Brodersen, Peter and Cademartiri, Ludovico and Thuo, Martin M. and Nijhuis, Christian A.}, year={2017}, month={Jul}, pages={1309–1315} }
 @inproceedings{thuo_2017, title={The Effect of Smoothening Electrodes on Tunneling Behaviors across Large Area Molecular Junctions}, booktitle={9th International Conference on Materials for Advanced Technologies (ICMAT}, author={Thuo, M.}, year={2017} }
 @article{çınar_schulz_oyola-reynoso_bwambok_gathiaka_thuo_2016, title={Application of Ionic Liquids in Pot-in-Pot Reactions}, volume={21}, DOI={10.3390/molecules21030272}, abstractNote={Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent for the target reaction. With the appropriate trigger, in most cases unidirectional flux, the product of the first reaction is introduced to the second medium allowing a second transformation in the same glass reaction pot—albeit separated by a polymeric membrane. The basis of these reaction systems is the controlled selective flux of one reagent over the other components of the first reaction while maintaining steady-state catalyst concentration in the first “pot”. The use of ionic liquids as tools to control chemical potential across the polymeric membranes making the first pot is discussed based on standard diffusion models—Fickian and Payne’s models. Besides chemical potential, use of ionic liquids as delivery agent for a small amount of a solvent that slightly swells the polymeric membrane, hence increasing flux, is highlighted. This review highlights the critical role ionic liquids play in site-isolation of multiple catalyzed reactions in a standard pot-in-pot reaction.}, number={3}, journal={Molecules}, publisher={MDPI AG}, author={Çınar, Simge and Schulz, Michael and Oyola-Reynoso, Stephanie and Bwambok, David and Gathiaka, Symon and Thuo, Martin}, year={2016}, month={Feb}, pages={272} }
 @inproceedings{thuo_2016, title={Biobased Adhesives and Coatings}, booktitle={American Coating Show}, author={Thuo, M.}, year={2016} }
 @inproceedings{thuo_2016, title={Coordination polymerization as a green and low-cost approach for synthesis of oxide structures with tunable porosity}, booktitle={European-Materials Research Society Meeting}, author={Thuo, M.}, year={2016} }
 @article{wang_chen_gathiaka_oyola-reynoso_thuo_2016, title={Effect of Substrate Morphology on the Odd–Even Effect in Hydrophobicity of Self-Assembled Monolayers}, volume={32}, ISSN={0743-7463 1520-5827}, url={http://dx.doi.org/10.1021/acs.langmuir.6b01681}, DOI={10.1021/acs.langmuir.6b01681}, abstractNote={Surface roughness, often captured through root-mean-square roughness (Rrms), has been shown to impact the quality of self-assembled monolayers (SAMs) formed on coinage metals. Understanding the effect of roughness on hydrophobicity of SAMs, however, is complicated by the odd-even effect-a zigzag oscillation in contact angles with changes in molecular length. We recently showed that for surfaces with Rrms > 1 nm, the odd-even effect in hydrophobicity cannot be empirically observed. In this report, we compare wetting properties of SAMs on Ag and Au surfaces of different morphologies across the Rrms ∼ 1 nm limit. We prepared surfaces with comparable properties (grain sizes and Rrms) and assessed the wetting properties of resultant SAMs. Substrates with Rrms either below or above the odd-even limit were investigated. With smoother surfaces (lower Rrms), an inverted asymmetric odd-even zigzag oscillation in static contact angles (θs) was observed with change from Au to Ag. Asymmetry in odd-even oscillation in Au was attributed to a larger change in θs from odd to even number of carbons in the n-alkanethiol and vice versa for Ag. For rougher surfaces, no odd-even effect was observed; however, a gradual increase in the static contact angle was observed. Increase in the average grain sizes (>3 times larger) on rough surfaces did not lead to significant difference in the wetting properties, suggesting that surface roughness significantly dominated the nature of the SAMs. We therefore infer that the predicted roughness-dependent limit to the observation of the odd-even effect in wetting properties of n-alkanethiols cannot be overcome by creating surfaces with large grain sizes for surfaces with Rrms > 1 nm. We also observed that the differences between Au and Ag surfaces are dominated by differences in the even-numbered SAMs, but this difference vanishes with shorter molecular chain length (≤C3).}, number={40}, journal={Langmuir}, publisher={American Chemical Society (ACS)}, author={Wang, Zhengjia and Chen, Jiahao and Gathiaka, Symon M. and Oyola-Reynoso, Stephanie and Thuo, Martin}, year={2016}, month={Sep}, pages={10358–10367} }
 @article{wang_chen_oyola-reynoso_thuo_2016, title={Empirical Evidence for Roughness-Dependent Limit in Observation of Odd–Even Effect in Wetting Properties of Polar Liquids on <i>n</i>-Alkanethiolate Self-Assembled Monolayers}, volume={32}, ISSN={0743-7463 1520-5827}, url={http://dx.doi.org/10.1021/acs.langmuir.6b02159}, DOI={10.1021/acs.langmuir.6b02159}, abstractNote={Substrate roughness influences the wetting properties of self-assembled monolayers (SAMs), but details on this dependency at the sub-nanometer level are still lacking. This study investigates the effect of surface roughness on interfacial properties of n-alkanethiolate SAMs, specifically wetting, and confirms the predicted limit to the observation of the odd-even effect in hydrophobicity. This article studies static contact angles of polar and nonpolar probe liquids on a series of n-alkanethiolate SAMs on surfaces with tunable roughness. We prepared Ag surfaces with root-mean-square roughness (Rrms) of ∼0.6-2.2 nm and compared the wetting properties of n-alkanethiolate SAMs fabricated on these surfaces. We measured the static contact angles, θs, formed between SAM and probe liquids [water, glycerol, and hexadecane]. Hexadecane showed an odd-even effect on all surfaces irrespective of the degree of roughness. Polar liquids (water and glycerol), however, showed a dependency on the roughness of the substrate with an odd-even effect observable only on smooth, but not rougher (Rrms ≥ 1.15 nm), surfaces. These results confirm that the previously predicted limit to observation of the odd-even effect in hydrophobicity (here extended to polar liquids) is real. From the results with glycerol, we infer that this limit is not limited just to hydrophobicity but may extend to other polar liquids. Results from hexadecane, however, suggest that this limit may not be a universal property of the SAM.}, number={32}, journal={Langmuir}, publisher={American Chemical Society (ACS)}, author={Wang, Zhengjia and Chen, Jiahao and Oyola-Reynoso, Stephanie and Thuo, Martin}, year={2016}, month={Aug}, pages={8230–8237} }
 @article{oyola-reynoso_tevis_chen_bloch_thuo_2016, title={Fabrication of Namib Beetle Inspired Biomimetic Amphi-phobic Surfaces Using Adsorbed Water as a Monomer}, volume={141}, DOI={10.1016/j.proeng.2015.08.1105}, abstractNote={Chemical grafting of small molecule reagents onto polymeric fibrous materials, like paper, has been used to modify their wetting properties. Several reagents like trichlorosilanes, which can react with water or hydroxyls, have been used with the expectation that a monolayer, single molecule or polymerized single-molecule layer, is formed on the paper fiber surface. Presence of adsorbed water, however, would complicate the formation of a monolayer, especially in case of polyvalent reagents. We hypothesized that adsorbed water is a good co-monomer for polyvalent water-reactive reagents, therefore chemical grafting with polyvalent molecules would give polymeric gels instead of a monolayer. Reaction of trivalent reagents with paper in vacuo leads to formation of polymeric gels. By optimizing surface energy mismatch, through felicitous choice of chemical moieties on the monomer, self-assembly leads to formation of nano- to micro particles on the surface of paper fibers. We observe that, as expected, the wetting properties correlate well with the size and distribution of particles. We conclude that the recently reported ultra-hydrophobicity of chemically modified paper is not only due to inherent roughness of the paper fibers, but also due to a secondary roughness introduced by surface polymerization. Using this technique, we prepared amphi-phobic biomimetic surfaces inspired by the namib beetle. This talk will also address potential utility of such surfaces.}, journal={Procedia Engineering}, publisher={Elsevier BV}, author={Oyola-Reynoso, Stephanie and Tevis, Ian and Chen, Jiahao and Bloch, Jean Francis and Thuo, Martin}, year={2016}, pages={59–62} }
 @inproceedings{thuo_2016, title={Fabrication of core-shell undercooled particles & their use in manufacturing and joining at ambient conditions}, booktitle={European-Materials Research Society Meeting}, author={Thuo, M.}, year={2016} }
 @article{chen_oyola-reynoso_thuo_2016, title={Introduction to Plant Oils}, DOI={10.1016/b978-0-323-35833-0.00001-3}, abstractNote={Plant oils can be classified into two broad classes based on their biosynthetic origins. Fatty acids- and glycerides-based oils are important for bulk materials synthesis industry while isoprenoid-based oils are important in the perfume and fragrance industry. Understanding their biosynthetic origin, reactivity, and market potential, can motivate the utility of both classes of plant oils in materials synthesis. This chapter reviews the biosynthesis, reactivity, characterization, processing (both small-scale and large-scale) and offers a future outlook of the potential of plant oils.}, journal={Bio-Based Plant Oil Polymers and Composites}, publisher={Elsevier BV}, author={Chen, Jiahao and Oyola-Reynoso, Stephanie and Thuo, Martin}, year={2016}, pages={1–18} }
 @article{çınar_tevis_chen_thuo_2016, title={Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering}, volume={6}, DOI={10.1038/srep21864}, abstractNote={Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate ('/' = physisorbed, '-' = chemisorbed), from molten Field's metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.}, journal={Sci. Rep.}, publisher={Nature Publishing Group}, author={Çınar, Simge and Tevis, Ian D. and Chen, Jiahao and Thuo, Martin}, year={2016}, month={Feb}, pages={21864} }
 @inbook{zhao_thuo_liu_2016, place={Cham, Switzerland}, title={Microfluidic Paper-Based Multiplexing Biosensors for Electrochemical Detection of Metabolic Biomarkers}, ISBN={9783319300177 9783319300191}, url={http://dx.doi.org/10.1007/978-3-319-30019-1_10}, DOI={10.1007/978-3-319-30019-1_10}, booktitle={Microfluidic Methods for Molecular Biology}, publisher={Springer International Publishing}, author={Zhao, Chen and Thuo, Martin M. and Liu, Xinyu}, editor={Lu, Chang and Verbridge, Scott S.Editors}, year={2016}, pages={205–218} }
 @inproceedings{thuo_2016, place={Long Beach, Ca}, title={Paper-based Microfluidic devices by pen calendaring}, booktitle={SACNAS Conference}, author={Thuo, M.}, year={2016} }
 @article{rossini_hanrahan_thuo_2016, title={Rapid acquisition of wideline MAS solid-state NMR spectra with fast MAS, proton detection, and dipolar HMQC pulse sequences}, volume={18}, ISSN={1463-9076 1463-9084}, url={http://dx.doi.org/10.1039/c6cp04279a}, DOI={10.1039/c6cp04279a}, abstractNote={The solid-state NMR spectra of many NMR active elements are often extremely broad due to the presence of chemical shift anisotropy (CSA) and/or the quadrupolar interaction (for nuclei with spin I > 1/2). These NMR interactions often give rise to wideline solid-state NMR spectra which can span hundreds of kHz or several MHz. Here we demonstrate that by using fast MAS, proton detection and dipolar hetero-nuclear multiple-quantum (D-HMQC) pulse sequences, it is possible to rapidly acquire 2D spectra which correlate 1H chemical shifts to the indirectly detected wideline MAS powder patterns of dipolar coupled hetero-nuclei. The D-HMQC pulse sequence enables broadband excitation of the wideline hetero-nuclear NMR spectrum and provides higher sensitivity by detecting the narrower and more sensitive 1H NMR signal. This approach is demonstrated for the rapid acquisition of 2D 1H detected 195Pt solid-state NMR spectra of cisplatin and transplatin and the 71Ga solid-state NMR spectrum of a self-assembled Ga coordination polymer of unconfirmed structure. This approach should be broadly applicable for the rapid acquisition of wideline MAS solid-state NMR spectra of moderately abundant NMR nuclei.}, number={36}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Rossini, Aaron J. and Hanrahan, Michael P. and Thuo, Martin}, year={2016}, pages={25284–25295} }
 @article{oyola-reynoso_tevis_chen_chang_çinar_bloch_thuo_2016, title={Recruiting physisorbed water in surface polymerization for bio-inspired materials of tunable hydrophobicity}, volume={4}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/c6ta06446a}, DOI={10.1039/c6ta06446a}, abstractNote={Chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications.}, number={38}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={Oyola-Reynoso, S. and Tevis, I. D. and Chen, J. and Chang, B. S. and Çinar, S. and Bloch, J.-F. and Thuo, M. M.}, year={2016}, pages={14729–14738} }
 @article{chen_tevis_gathiaka_thuo_2016, title={Stereo-Electronic Effects in Tunneling Junctions: Revisiting the Platform}, volume={141}, DOI={10.1016/j.proeng.2015.09.228}, abstractNote={Stereo-electronic effects in through-bond tunneling in large area molecular junctions have not been widely studied, largely due to a lack of a clear understanding of basic interfacial properties of self-assembled monolayers (SAMs) — the platform on which these junctions are built. Due to a large volume of work in SAMs, it has been largely assumed that their characteristics are well understood, among these, the so-called odd-even effect. This report demonstrates that there is still a lot to be done, or revisited, with regards to SAM formation, characterization, and, potential, if molecular junctions are to emerge as a useful technology. To illustrate this point, the Whitesides-Porter odd-even quandary of the early 90s (in SAM hydrophobicity) is revisited with a new set of data. An overview of recent efforts in our group to improve quality of tunneling junctions is also presented from three key perspective, viz; i) Surface: optimizing the surface roughness (Au, RMS roughness <2 Å). ii) Interface: studies on the properties of the unbound SAM interface. iii) Molecule: Engineering the stereo-electronic properties to reveal the role of conformational effects on tunneling currents.}, journal={Procedia Engineering}, publisher={Elsevier BV}, author={Chen, Jiahao and Tevis, Ian and Gathiaka, Symon and Thuo, Martin}, year={2016}, pages={138–143} }
 @inproceedings{thuo_2016, title={Stereo-electronic effects in charge transport through large-area junctions}, booktitle={251st ACS National Meeting & Exposition}, author={Thuo, M.}, year={2016} }
 @article{oyola-reynoso_kihereko_chang_mwangi_halbertsma-black_bloch_thuo_nganga_2016, title={Substituting Plastic Casings with Hydrophobic (Perfluorosilane treated) paper improves Biodegradability of Low-Cost Diagnostic Devices}, volume={94}, url={https://doi.org/10.1016/j.indcrop.2016.08.051}, DOI={10.1016/j.indcrop.2016.08.051}, abstractNote={The demand for rapid diagnostic in developing countries has recently increased, in part due to growing populations, emerging diseases, and rise in healthcare cost. Use of low-cost lateral flow/dipstick devices, especially paper-based ones, has increased. In most of the developing world, however, biomedical waste management systems either do not exist or are poor, as such, used devices either get incinerated or dumped alongside household trash. The plastic casing that is often used to hold the test strip, while useful before the test, also slows the biodegradation of the used contaminated devices. We demonstrate that by replacing the plastic casing with paper encasements, we promote biodegradation of these devices while reducing its total weight, making their transport and packaging more compact and more environmentally friendly—hence qualifying this simple modification as green engineering. The ability to use paper casing has the added advantage that devices can be readily assembled locally with ease and without need for sophisticated manufacturing tools as needed with the plastic casings.}, journal={Industrial Crops and Products}, publisher={Elsevier BV}, author={Oyola-Reynoso, Stephanie and Kihereko, Dickson and Chang, Boyce S. and Mwangi, James N. and Halbertsma-Black, Julian and Bloch, Jean-Francis and Thuo, Martin M. and Nganga, Margaret M.}, year={2016}, month={Dec}, pages={294–298} }
 @article{oyola-reynoso_chen_chang_bloch_thuo_2016, title={Surface polymerization of perfluorosilane treatments on paper mitigates HF production upon incineration}, volume={6}, ISSN={2046-2069}, url={http://dx.doi.org/10.1039/c6ra20582h}, DOI={10.1039/c6ra20582h}, abstractNote={Burning perfluoro trichlorosilanes (RF) treated paper leads to depolymerization of the crosslinked polysilane, distilling off liquid RF and emitting CO2 and H2O as the only gaseous products.}, number={85}, journal={RSC Advances}, publisher={Royal Society of Chemistry (RSC)}, author={Oyola-Reynoso, Stephanie and Chen, Jiahao and Chang, Boyce S. and Bloch, Jean-Francis and Thuo, Martin M.}, year={2016}, pages={82233–82237} }
 @article{j. mithila_oyola-reynoso_m. thuo_b.j. atkinson_2016, title={Visualization of Hyperconjugation and Subsequent Structural Distortions through 3D Printing of Crystal Structures}, volume={13}, ISSN={1570-1786}, url={http://dx.doi.org/10.2174/1570178613666160204010454}, DOI={10.2174/1570178613666160204010454}, abstractNote={BACKGROUND
Structural distortions due to hyperconjugation in organic molecules, like norbornenes, are well captured through X-ray crystallographic data, but are sometimes difficult to visualize especially for those applying chemical knowledge and are not chemists.


METHODS
Crystal structure from the Cambridge database were downloaded and converted to .stl format. The structures were then printed at the desired scale using a 3D printer.


RESULTS
Replicas of the crystal structures were accurately reproduced in scale and any resulting distortions were clearly visible from the macroscale models. Through space interactions or effect of through space hyperconjugation was illustrated through loss of symmetry or distortions thereof.


CONCLUSION
The norbornene structures exhibits distortion that cannot be observed through conventional ball and stick modelling kits. We show that 3D printed models derived from crystallographic data capture even subtle distortions in molecules. We translate such crystallographic data into scaled-up models through 3D printing.}, number={4}, journal={Letters in Organic Chemistry}, publisher={Bentham Science Publishers Ltd.}, author={J. Mithila, Farha and Oyola-Reynoso, Stephanie and M. Thuo, Martin and B.J. Atkinson, Manza}, year={2016}, month={Apr}, pages={272–276} }
 @inproceedings{thuo_2015, title={A simple mechanical annealing to fabricate large area super flat metal surface}, booktitle={1st International Conference on Applied Surface Science}, author={Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, title={Biomimetic Amphiphobic Surfaces on Paper}, booktitle={249th American Chemical Society Conference, National Meeting & Exposition}, author={Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, title={Biomimetic Namib beetle inspired omniphobic paper and related technologies}, booktitle={8th African Materials Research Society Meeting}, author={Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, title={Chemical and Mechanical Surface Modification for Low-cost bio-analytical devices}, booktitle={American Chemical Society regional meeting}, author={Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, place={Natal, RN}, title={Development of new catalyst-monomer pairs for bio-renewable thermoset production by ROMP}, booktitle={13 Congresso Brasileiro de Polímeros}, author={Thuo, M.}, year={2015} }
 @article{oyola-reynoso_heim_halbertsma-black_zhao_tevis_çınar_cademartiri_liu_bloch_thuo_2015, title={Draw your assay: Fabrication of low-cost paper-based diagnostic and multi-well test zones by drawing on a paper}, volume={144}, DOI={10.1016/j.talanta.2015.06.018}, abstractNote={Interest in low-cost diagnostic devices has recently gained attention, in part due to the rising cost of healthcare and the need to serve populations in resource-limited settings. A major challenge in the development of such devices is the need for hydrophobic barriers to contain polar bio-fluid analytes. Key approaches in lowering the cost in diagnostics have centered on (i) development of low-cost fabrication techniques/processes, (ii) use of affordable materials, or, (iii) minimizing the need for high-tech tools. This communication describes a simple, low-cost, adaptable, and portable method for patterning paper and subsequent use of the patterned paper in diagnostic tests. Our approach generates hydrophobic regions using a ball-point pen filled with a hydrophobizing molecule suspended in a solvent carrier. An empty ball-point pen was filled with a solution of trichloro perfluoroalkyl silane in hexanes (or hexadecane), and the pen used to draw lines on Whatman® chromatography 1 paper. The drawn regions defined the test zones since the trichloro silane reacts with the paper to give a hydrophobic barrier. The formation of the hydrophobic barriers is reaction kinetic and diffusion-limited, ensuring well defined narrow barriers. We performed colorimetric glucose assays and enzyme-linked immuno-sorbent assay (ELISA) using the created test zones. To demonstrate the versatility of this approach, we fabricated multiple devices on a single piece of paper and demonstrated the reproducibility of assays on these devices. The overall cost of devices fabricated by drawing are relatively lower (<US $0.001 per device) than those derived from wax-printing (US$0.05-0.003) or other approaches.}, journal={Talanta}, publisher={Elsevier BV}, author={Oyola-Reynoso, Stephanie and Heim, Andrew P. and Halbertsma-Black, Julian and Zhao, C. and Tevis, Ian D. and Çınar, Simge and Cademartiri, Rebecca and Liu, Xinyu and Bloch, Jean-Francis and Thuo, Martin M.}, year={2015}, month={Nov}, pages={289–293} }
 @inproceedings{thuo_2015, title={Fabrication of Namib Beetle Inspired Biomimetic Amphi-Phobic Surfaces Using Adsorbed Water as a Monomer}, booktitle={8th International Conference on Materials for Advanced Technologies}, author={Thuo, M.}, year={2015} }
 @article{chen_wang_oyola-reynoso_gathiaka_thuo_2015, title={Limits to the Effect of Substrate Roughness or Smoothness on the Odd–Even Effect in Wetting Properties of n -Alkanethiolate Monolayers}, volume={31}, DOI={10.1021/acs.langmuir.5b01662}, abstractNote={This study investigates the effect of roughness on interfacial properties of an n-alkanethiolate self-assembled monolayer (SAM) and uses hydrophobicity to demonstrate the existence of upper and lower limits. This article also sheds light on the origin of the previously unexplained gradual increase in contact angles with increases in the size of the molecule making the SAM. We prepared Au surfaces with a root-mean-square (RMS) roughness of ∼0.2-0.5 nm and compared the wetting properties of n-alkanethiolate (C10-C16) SAMs fabricated on these surfaces. Static contact angles, θ(s), formed between the SAM and water, diethylene glycol, and hexadecane showed an odd-even effect irrespective of the solvent properties. The average differences in subsequent SAM(E) and SAM(O) are Δθ(s|n  – (n+1)|) ≈ 1.7° (n = even) and Δθ(s|n – (n+1)|) ≈ 3.1° (n = odd). A gradual increase in θ(s) with increasing length of the molecule was observed, with values ranging from water 104.7-110.7° (overall Δθ(s) = 6.0° while for the evens Δθ(s)(E) = 4.4° and odds Δθ(s)(O) = 3.5°) to diethylene glycol 72.9-80.4° (overall Δθ(s) = 7.5° while for the evens Δθ(s)(E) = 2.9° and odds Δθ(s)(O) = 2.4°) and hexadecane 40.4–49.4° (overall Δθ(s) = 9.0° while for the evens Δθ(s)(E) = 3.7° and odds Δθ(s)(O) = 2.1°). This article establishes that the gradual increase in θ(s) with increasing molecular size in SAMs is due to asymmetry in the zigzag oscillation in the odd-even effect. Comparison of the magnitude and proportion differences in this asymmetry allows us to establish the reduction in interfacial dispersive forces, due to increasing SAM crystallinity with increasing molecular size, as the origin of this asymmetry. By comparing the dependence of θ(s) on surface roughness we infer that (i) RMS roughness ≈ 1 nm is a theoretical limit beyond which the odd-even effect cannot be observed and (ii) on a hypothetically flat surface the maximum difference in hydrophobicity, as expressed in θ(s), is ∼3°.}, number={25}, journal={Langmuir}, publisher={American Chemical Society (ACS)}, author={Chen, Jiahao and Wang, Zhengjia and Oyola-Reynoso, Stephanie and Gathiaka, Symon M. and Thuo, Martin}, year={2015}, month={Jun}, pages={7047–7054} }
 @inproceedings{thuo_2015, title={Limits to the influence of surface roughness on the odd-even effect in wetting properties of self-assembled monolayers}, booktitle={1st International Conference on Applied Surface Science}, author={Thuo, M.}, year={2015} }
 @article{li_tevis_oyola-reynoso_newcomb_halbertsma-black_bloch_thuo_2015, title={Melt-and-mold fabrication (MnM-Fab) of reconfigurable low-cost devices for use in resource-limited settings}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84930012316&partnerID=MN8TOARS}, DOI={10.1016/j.talanta.2015.05.002}, abstractNote={Interest in low-cost analytical devices (especially for diagnostics) has recently increased; however, concomitant translation to the field has been slow, in part due to personnel and supply-chain challenges in resource-limited settings. Overcoming some of these challenges require the development of a method that takes advantage of locally available resources and/or skills. We report a Melt-and-mold fabrication (MnM Fab) approach to low-cost and simple devices that has the potential to be adapted locally since it requires a single material that is recyclable and simple skills to access multiple devices. We demonstrated this potential by fabricating entry level bio-analytical devices using an affordable low-melting metal alloy, Field's metal, with molds produced from known materials such as plastic (acrylonitrile–butadiene–styrene (ABS)), glass, and paper. We fabricated optical gratings then 4×4 well plates using the same recycled piece of metal. We then reconfigured the well plates into rapid prototype microfluidic devices with which we demonstrated laminar flow, droplet generation, and bubble formation from T-shaped channels. We conclude that this MnM-Fab method is capable of addressing some challenges typically encountered with device translation, such as technical know-how or material supply, and that it can be applied to other devices, as needed in the field, using a single moldable material.}, journal={Talanta}, author={Li, Z. and Tevis, I.D. and Oyola-Reynoso, S. and Newcomb, L.B. and Halbertsma-Black, J. and Bloch, J.-F. and Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, place={Boston, MA, United States}, title={Nano-mechanical properties of eutectic gallium-indium particles by atomic forcemicroscopy}, booktitle={250th American Chemical Society National Meeting & Exposition}, author={Thuo, M.}, year={2015} }
 @inproceedings{thuo_2015, title={Particles for joining and manufacturing of metals at room temperature}, booktitle={2nd Midwest Postdoctoral Symposium}, author={Thuo, M.}, year={2015}, month={May} }
 @article{atkinson_oyola-reynoso_luna_bwambok_thuo_2015, title={Pot-in-pot reactions: a simple and green approach to efficient organic synthesis}, volume={5}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000345924600071&KeyUID=WOS:000345924600071}, DOI={10.1039/c4ra13506g}, abstractNote={Incompatible organic reactions impede efficient green synthesis by making multi-component or cascade reactions a big challenge. This review highlights pot-in-pot reactions (multiple reactions carried out in one pot by separating key reactions with a thin polymeric membrane) as an efficient, green synthetic alternative to conventional synthesis. We discuss the advantages of homogeneous processes to develop new cascade reaction sequences by reviewing the use of polymeric thimbles as selective semi-permeable walls. These thimbles allow small organic molecules to diffuse through while retaining polar reagents, polar solvents, and/or organometallic catalysts. The dynamic and versatile nature of this technique is demonstrated by performing 2- and 3-step cascade reactions in one glass pot. A pot-in-pot reaction approach to synthesis circumvents the need to isolate intermediates, or handling of toxic/unpleasant by-products, therefore enabling synthesis of otherwise challenging molecules, improving the efficiency, or enabling greener approaches to modular synthesis.}, number={1}, journal={Rsc Advances}, author={Atkinson, M. B. J. and Oyola-Reynoso, S. and Luna, R. E. and Bwambok, D. K. and Thuo, M. M.}, year={2015}, pages={597–607} }
 @article{oyola-reynoso_heim_halbertsma-black_zhao_tevis_çınar_cademartiri_liu_bloch_thuo_2015, title={Reprint of 'Draw your assay: Fabrication of low-cost paper-based diagnostic and multi-well test zones by drawing on a paper'}, volume={145}, DOI={10.1016/j.talanta.2015.09.042}, abstractNote={Interest in low-cost diagnostic devices has recently gained attention, in part due to the rising cost of healthcare and the need to serve populations in resource-limited settings. A major challenge in the development of such devices is the need for hydrophobic barriers to contain polar bio-fluid analytes. Key approaches in lowering the cost in diagnostics have centered on (i) development of low-cost fabrication techniques/processes, (ii) use of affordable materials, or, (iii) minimizing the need for high-tech tools. This communication describes a simple, low-cost, adaptable, and portable method for patterning paper and subsequent use of the patterned paper in diagnostic tests. Our approach generates hydrophobic regions using a ball-point pen filled with a hydrophobizing molecule suspended in a solvent carrier. An empty ball-point pen was filled with a solution of trichloro perfluoroalkyl silane in hexanes (or hexadecane), and the pen used to draw lines on Whatman® chromatography 1 paper. The drawn regions defined the test zones since the trichloro silane reacts with the paper to give a hydrophobic barrier. The formation of the hydrophobic barriers is reaction kinetic and diffusion-limited, ensuring well defined narrow barriers. We performed colorimetric glucose assays and enzyme-linked immuno-sorbent assay (ELISA) using the created test zones. To demonstrate the versatility of this approach, we fabricated multiple devices on a single piece of paper and demonstrated the reproducibility of assays on these devices. The overall cost of devices fabricated by drawing are relatively lower (<US $0.001 per device) than those derived from wax-printing (US$0.05-0.003) or other approaches.}, journal={Talanta}, publisher={Elsevier BV}, author={Oyola-Reynoso, Stephanie and Heim, Andrew P. and Halbertsma-Black, Julian and Zhao, C. and Tevis, Ian D. and Çınar, Simge and Cademartiri, Rebecca and Liu, Xinyu and Bloch, Jean-Francis and Thuo, Martin M.}, year={2015}, pages={73–77} }
 @article{sporrer_chen_wang_thuo_2015, title={Revealing the Nature of Molecule–Electrode Contact in Tunneling Junctions Using Raw Data Heat Maps}, volume={6}, DOI={10.1021/acs.jpclett.5b02300}, abstractNote={Mechanistic understanding of charge transport through molecular tunnel junctions requires reproducible and statistically relevant data sets. This challenge has been overcome by development of large area junctions, especially those based on liquid-metal physi-sorbed top-electrodes, such as eutectic gallium-indium. A challenge with these junctions, however, is an inability to diagnose the quality of contact between the top-electrode and the SAMs. Since tunneling currents are dependent on the distance between the two electrodes, we demonstrate that by analyzing all raw unfitted data derived from a measurement using heat-maps, one can deduce the quality of contact and other minor bias-dependent fluctuations in the charge transport behavior. We demonstrate that the use of 3D plots would be challenging to interpret, but adoption of heat maps clearly captures details on junction quality irrespective of the total size of the data set or molecules used. We propose representation of raw data, rather than reliance on statistics, as proof of quality junctions.}, number={24}, journal={J. Phys. Chem. Lett.}, publisher={American Chemical Society (ACS)}, author={Sporrer, Jacob and Chen, Jiahao and Wang, Zhengjia and Thuo, Martin M.}, year={2015}, pages={4952–4958} }
 @article{oyola-reynoso_wang_chen_çınar_chang_thuo_2015, title={Revisiting the Challenges in Fabricating Uniform Coatings with Polyfunctional Molecules on High Surface Energy Materials}, volume={5}, DOI={10.3390/coatings5041002}, abstractNote={Modifying the chemistry of a surface has been widely used to influence interfacial properties of a material or nature of interaction between two materials. This article provides an overview on the role of polyfunctional molecules, specifically silanes, in surface modification of polar surfaces (bearing soft nucleophiles). An emphasis on the mechanism of the reaction in the presence of adsorbed water, where the modifying reagents are hydrolysable, is discussed. To highlight the complexity of the reaction, modification of paper with trichlorosilanes is highlighted. Preparation of hydrophobic cellulosic paper, and structure–property relations under different treatment conditions is used to highlight that a monolayer is not always formed during the surface modification. Gel-formation via step-growth polymerization suggests that at the right monomer:adsorbed water ratio, a monolayer will not form but rather self-assembly driven particle formation will occur leading to a textured surface. The review highlights recent work indicating that the focus on monolayer formation, is at the very least, not always the case but gel formation, with concomitant self-assembly, might be the culprit in understanding challenges associated with the use of polyfunctional molecules in surface modification.}, number={4}, journal={Coatings}, publisher={MDPI AG}, author={Oyola-Reynoso, Stephanie and Wang, Zhengjia and Chen, Jiahao and Çınar, Simge and Chang, Boyce and Thuo, Martin}, year={2015}, pages={1002–1018} }
 @inproceedings{thuo_2015, title={Stereo-electronic effects in charge transport through large-area junctions}, booktitle={8th African Materials Research Society Meeting}, author={Thuo, M.}, year={2015} }
 @article{wang_chen_oyola-reynoso_thuo_2015, title={The Porter-Whitesides Discrepancy: Revisiting Odd-Even Effects in Wetting Properties of n-Alkanethiolate SAMs}, volume={5}, DOI={10.3390/coatings5041034}, abstractNote={This review discusses the Porter-Whitesides discrepancy in wetting properties of n-alkanethiolate self-assembled monolayers (SAMs). About 25 years ago, Whitesides and coworker failed to observe any odd-even effect in wetting, however, Porter and his coworker did, albeit in select cases. Most previous studies agreed with Whitesides’ results, suggesting the absence of the odd-even effect in hydrophobicity of n-alkanethiolate SAMs. Recent reports have, however, found the odd-even effect in hydrophobicity of n-alkanethiolate SAMs on smooth substrates, indicating that hydrophobicity, and analogous interfacial properties, of n-alkanethiolate SAMs significantly depends on the properties of substrate. Unfortunately, the Whitesides and Porter papers do not report on the quality of the surfaces used. Based on recent work, we inferred that the original discrepancy between Whitesides and Porter can be attributed to the quality of the surface. Odd-even effect of SAMs in charge transport, capacitance, friction, and SAM structure are also discussed in this review to inform the general discussion. The discrepancy between Porter's group and Whitesides’ group could be due to surface roughness, morphology, oxidation, and adventitious contaminants.}, number={4}, journal={Coatings}, publisher={MDPI AG}, author={Wang, Zhengjia and Chen, Jiahao and Oyola-Reynoso, Stephanie and Thuo, Martin}, year={2015}, pages={1034–1055} }
 @inproceedings{thuo_2015, title={Topographical changes of liquid-metal alloys as a function of temperature}, booktitle={250th American Chemical Society National Meeting & Exposition}, author={Thuo, M.}, year={2015} }
 @inproceedings{brose_thuo_sheaffer_2015, title={Tracking water droplets under descent and deformation}, DOI={10.1145/2787626.2787651}, abstractNote={We present a system for tracking the movement and deformation of drops of water in free fall and collision. Our data comes from a high-speed camera which records 60,000 frames per second. The data is noisy, and is compromised by an unfortunate camera angle and poor lighting which contribute to caustics, reflections, and shadows in the image. Given an input video, we apply techniques from image processing, computer vision and computational geometry to track the the droplet's position and shape. While our tool could monitor the movement of transparent fluids in a more general environment, our data specifically depicts water colliding with hydrophobic materials. The output of our processing is used by materials scientists to better our understanding of the interactions between water and hydrophobic surfaces. These interactions have direct application in the materials engineering of next generation printing technologies.}, booktitle={ACM SIGGRAPH 2015 Posters on - SIGGRAPH '15}, publisher={Association for Computing Machinery (ACM)}, author={Brose, Caleb and Thuo, Martin and Sheaffer, Jeremy W.}, year={2015} }
 @article{schulz_atkinson_elsey_thuo_2014, title={Copper(I) halides inhibit olefin isomerized by-products from phosphine-based Grubbs' metathesis catalysts in polar protic solvents}, volume={39}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000341844300007&KeyUID=WOS:000341844300007}, DOI={10.1007/s11243-014-9858-1}, number={7}, journal={Transition Metal Chemistry}, author={Schulz, Michael D. and Atkinson, Manza B. J. and Elsey, Rachel J. and Thuo, Martin M.}, year={2014}, pages={763–767} }
 @article{thuo_martinez_lan_liu_barber_atkinson_bandarage_bloch_whitesides_2014, title={Fabrication of low-cost paper-based microfluidic devices by embossing or cut-and-stack methods}, volume={26}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84904632121&partnerID=MN8TOARS}, DOI={10.1021/cm501596s}, abstractNote={This article describes the use of embossing and “cut-and-stack” methods of assembly, to generate microfluidic devices from omniphobic paper and demonstrates that fluid flowing through these devices behaves similarly to fluid in an open-channel microfluidic device. The porosity of the paper to gases allows processes not possible in devices made using PDMS or other nonporous materials. Droplet generators and phase separators, for example, could be made by embossing “T”-shaped channels on paper. Vertical stacking of embossed or cut layers of omniphobic paper generated three-dimensional systems of microchannels. The gas permeability of the paper allowed fluid in the microchannel to contact and exchange with environmental or directed gases. An aqueous stream of water containing a pH indicator, as one demonstration, changed color upon exposure to air containing HCl or NH3 gases.}, number={14}, journal={Chemistry of Materials}, author={Thuo, M.M. and Martinez, R.V. and Lan, W.-J. and Liu, X. and Barber, J. and Atkinson, M.B.J. and Bandarage, D. and Bloch, J.-F. and Whitesides, G.M.}, year={2014}, pages={4230–4237} }
 @article{barber_yoon_bowers_thuo_breiten_gooding_whitesides_2014, title={Influence of Environment on the Measurement of Rates of Charge Transport across Ag-TS/SAM//Ga2O3/EGaln Junctions}, volume={26}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000338806700012&KeyUID=WOS:000338806700012}, DOI={10.1021/cm5014784}, abstractNote={This paper investigates the influence of the atmosphere used in the fabrication of top electrodes from the liquid eutectic of gallium and indium (EGaIn) (the so-called “EGaIn” electrodes), and in measurements of current density, J(V) (A/cm2), across self-assembled monolayers (SAMs) incorporated into Ag/SR//Ga2O3/EGaIn junctions, on values of J(V) obtained using these electrodes. A gas-tight measurement chamber was used to control the atmosphere in which the electrodes were formed, and also to control the environment in which the electrodes were used to measure current densities across SAM-based junctions. Seven different atmospheres—air, oxygen, nitrogen, argon, and ammonia, as well as air containing vapors of acetic acid or water—were surveyed using both “rough” conical-tip electrodes, and “smooth” hanging-drop electrodes. (The manipulation of the oxide film during the creation of the conical-tip electrodes leads to substantial, micrometer-scale roughness on the surface of the electrode, the extrusion of...}, number={13}, journal={Chemistry of Materials}, author={Barber, Jabulani R. and Yoon, Hyo Jae and Bowers, Carleen M. and Thuo, Martin M. and Breiten, Benjamin and Gooding, Diana M. and Whitesides, George M.}, year={2014}, pages={3938–3947} }
 @article{newcomb_tevis_atkinson_gathiaka_luna_thuo_2014, title={Odd-Even Effect in the Hydrophobicity of n-Alkanethiolate Self-Assembled Monolayers Depends upon the Roughness of the Substrate and the Orientation of the Terminal Moiety}, volume={30}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000343195800018&KeyUID=WOS:000343195800018}, DOI={10.1021/la5032569}, abstractNote={The origin of the odd-even effect in properties of self-assembled monolayers (SAMs) and/or technologies derived from them is poorly understood. We report that hydrophobicity and, hence, surface wetting of SAMs are dominated by the nature of the substrate (surface roughness and identity) and SAM tilt angle, which influences surface dipoles/orientation of the terminal moiety. We measured static contact angles (θs) made by water droplets on n-alkanethiolate SAMs with an odd (SAM(O)) or even (SAM(E)) number of carbons (average θs range of 105.8-112.1°). When SAMs were fabricated on smooth "template-stripped" metal (M(TS)) surfaces [root-mean-square (rms) roughness = 0.36 ± 0.01 nm for Au(TS) and 0.60 ± 0.04 nm for Ag(TS)], the odd-even effect, characterized by a zigzag oscillation in values of θs, was observed. We, however, did not observe the same effect with rougher "as-deposited" (M(AD)) surfaces (rms roughness = 2.27 ± 0.16 nm for Au(AD) and 5.13 ± 0.22 nm for Ag(AD)). The odd-even effect in hydrophobicity inverts when the substrate changes from Au(TS) (higher θs for SAM(E) than SAM(O), with average Δθs |n - (n + 1)| ≈ 3°) to Ag(TS) (higher θs for SAM(O) than SAM(E), with average Δθs |n - (n + 1)| ≈ 2°). A comparison of hydrophobicity across Ag(TS) and Au(TS) showed a statistically significant difference (Student's t test) between SAM(E) (Δθs |Ag evens - Au evens| ≈ 5°; p < 0.01) but failed to show statistically significant differences on SAM(O) (Δθs |Ag odds - Au odds| ≈ 1°; p > 0.1). From these results, we deduce that the roughness of the metal substrate (from comparison of M(AD) versus M(TS)) and orientation of the terminal -CH2CH3 (by comparing SAM(E) and SAM(O) on Au(TS) versus Ag(TS)) play major roles in the hydrophobicity and, by extension, general wetting properties of n-alkanethiolate SAMs.}, number={40}, journal={Langmuir}, author={Newcomb, Lucas B. and Tevis, Ian D. and Atkinson, Manza B. J. and Gathiaka, Symon M. and Luna, Rafael E. and Thuo, Martin}, year={2014}, pages={11985–11992} }
 @article{baghbanzadeh_simeone_bowers_liao_thuo_baghbanzadeh_miller_carmichael_whitesides_2014, title={Odd-Even Effects in Charge Transport across n-Alkanethiolate-Based SAMs}, volume={136}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000345883900038&KeyUID=WOS:000345883900038}, DOI={10.1021/ja509436k}, abstractNote={This paper compares rates of charge transport across self-assembled monolayers (SAMs) of n-alkanethiolates having odd and even numbers of carbon atoms (nodd and neven) using junctions with the structure M(TS)/SAM//Ga2O3/EGaIn (M = Au or Ag). Measurements of current density, J(V), across SAMs of n-alkanethiolates on Au(TS) and Ag(TS) demonstrated a statistically significant odd-even effect on Au(TS), but not on Ag(TS), that could be detected using this technique. Statistical analysis showed the values of tunneling current density across SAMs of n-alkanethiolates on Au(TS) with nodd and neven belonging to two separate sets, and while there is a significant difference between the values of injection current density, J0, for these two series (log|J0Au,even| = 4.0 ± 0.3 and log|J0Au,odd| = 4.5 ± 0.3), the values of tunneling decay constant, β, for nodd and neven alkyl chains are indistinguishable (βAu,even = 0.73 ± 0.02 Å(-1), and βAu,odd= 0.74 ± 0.02 Å(-1)). A comparison of electrical characteristics across junctions of n-alkanethiolate SAMs on gold and silver electrodes yields indistinguishable values of β and J0 and indicates that a change that substantially alters the tilt angle of the alkyl chain (and, therefore, the thickness of the SAM) has no influence on the injection current density across SAMs of n-alkanethiolates.}, number={48}, journal={Journal of the American Chemical Society}, author={Baghbanzadeh, Mostafa and Simeone, Felice C. and Bowers, Carleen M. and Liao, Kung-Ching and Thuo, Martin and Baghbanzadeh, Mahdi and Miller, Michael S. and Carmichael, Tricia Breen and Whitesides, George M.}, year={2014}, pages={16919–16925} }
 @article{glavan_martinez_subramaniam_yoon_nunes_lange_thuo_whitesides_2014, title={Omniphobic "R-F Paper" Produced by Silanization of Paper with Fluoroalkyltrichlorosilanes}, volume={24}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000330589300006&KeyUID=WOS:000330589300006}, DOI={10.1002/adfm.201300780}, abstractNote={The fabrication and properties of “fluoroalkylated paper” (“RF paper”) by vapor‐phase silanization of paper with fluoroalkyl trichlorosilanes is reported. RF paper is both hydrophobic and oleophobic: it repels water (θappH2O>140°), organic liquids with surface tensions as low as 28 mN m‐1, aqueous solutions containing ionic and non‐ionic surfactants, and complex liquids such as blood (which contains salts, surfactants, and biological material such as cells, proteins, and lipids). The propensity of the paper to resist wetting by liquids with a wide range of surface tensions correlates with the length and degree of fluorination of the organosilane (with a few exceptions in the case of methyl trichlorosilane‐treated paper), and with the roughness of the paper. RF paper maintains the high permeability to gases and mechanical flexibility of the untreated paper, and can be folded into functional shapes (e.g., microtiter plates and liquid‐filled gas sensors). When impregnated with a perfluorinated oil, RF paper forms a “slippery” surface (paper slippery liquid‐infused porous surface, or “paper SLIPS“) capable of repelling liquids with surface tensions as low as 15 mN m‐1. The foldability of the paper SLIPS allows the fabrication of channels and flow switches to guide the transport of liquid droplets.}, number={1}, journal={Advanced Functional Materials}, author={Glavan, Ana C. and Martinez, Ramses V. and Subramaniam, Anand Bala and Yoon, Hyo Jae and Nunes, Rui M. D. and Lange, Heiko and Thuo, Martin M. and Whitesides, George M.}, year={2014}, pages={60–70} }
 @article{tevis_newcomb_thuo_2014, title={Synthesis of Liquid Core Shell Particles and Solid Patchy Multicomponent Particles by Shearing Liquids Into Complex Particles (SLICE)}, volume={30}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000345803500026&KeyUID=WOS:000345803500026}, DOI={10.1021/la5035118}, abstractNote={We report a simple method that uses (i) emulsion shearing with oxidation to make core-shell particles, and (ii) emulsion shearing with surface-tension driven phase segregation to synthesize particles with complex surface compositions and morphologies. Subjecting eutectic gallium-indium, a liquid metal, to shear in an acidic carrier fluid we synthesized smooth liquid core-shell particles 6.4 nm to over 10 μm in diameter. Aggregates of these liquid particles can be reconfigured into larger structures using a focused ion beam. Using Field's metal melts we synthesized homogeneous nanoparticles and solid microparticles with different surface roughness and/or composition through shearing and phase separation. This extension of droplet emulsion technique, SLICE, applies fluidic shear to create micro- and nanoparticles in a tunable, green, and low-cost approach.}, number={47}, journal={Langmuir}, author={Tevis, Ian D. and Newcomb, Lucas B. and Thuo, Martin}, year={2014}, pages={14308–14313} }
 @article{zhao_thuo_liu_2013, title={A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84887110870&partnerID=MN8TOARS}, DOI={10.1088/1468-6996/14/5/054402}, abstractNote={Abstract Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way.}, number={5}, journal={Science and Technology of Advanced Materials}, author={Zhao, C. and Thuo, M.M. and Liu, X.}, year={2013} }
 @article{simeone_yoon_thuo_barber_smith_whitesides_2013, title={Defining the Value of Injection Current and Effective Electrical Contact Area for EGaln-Based Molecular Tunneling Junctions}, volume={135}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000328100000023&KeyUID=WOS:000328100000023}, DOI={10.1021/ja408652h}, abstractNote={Analysis of rates of tunneling across self-assembled monolayers (SAMs) of n-alkanethiolates SCn (with n = number of carbon atoms) incorporated in junctions having structure Ag(TS)-SAM//Ga2O3/EGaIn leads to a value for the injection tunnel current density J0 (i.e., the current flowing through an ideal junction with n = 0) of 10(3.6±0.3) A·cm(-2) (V = +0.5 V). This estimation of J0 does not involve an extrapolation in length, because it was possible to measure current densities across SAMs over the range of lengths n = 1-18. This value of J0 is estimated under the assumption that values of the geometrical contact area equal the values of the effective electrical contact area. Detailed experimental analysis, however, indicates that the roughness of the Ga2O3 layer, and that of the Ag(TS)-SAM, determine values of the effective electrical contact area that are ~10(-4) the corresponding values of the geometrical contact area. Conversion of the values of geometrical contact area into the corresponding values of effective electrical contact area results in J0(+0.5 V) = 10(7.6±0.8) A·cm(-2), which is compatible with values reported for junctions using top-electrodes of evaporated Au, and graphene, and also comparable with values of J0 estimated from tunneling through single molecules. For these EGaIn-based junctions, the value of the tunneling decay factor β (β = 0.75 ± 0.02 Å(-1); β = 0.92 ± 0.02 nC(-1)) falls within the consensus range across different types of junctions (β = 0.73-0.89 Å(-1); β = 0.9-1.1 nC(-1)). A comparison of the characteristics of conical Ga2O3/EGaIn tips with the characteristics of other top-electrodes suggests that the EGaIn-based electrodes provide a particularly attractive technology for physical-organic studies of charge transport across SAMs.}, number={48}, journal={Journal of the American Chemical Society}, author={Simeone, Felice C. and Yoon, Hyo Jae and Thuo, Martin M. and Barber, Jabulani R. and Smith, Barbara and Whitesides, George M.}, year={2013}, pages={18131–18144} }
 @article{bwambok_thuo_atkinson_mirica_shapiro_whitesides_2013, title={Paramagnetic Ionic Liquids for Measurements of Density Using Magnetic Levitation}, volume={85}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000330017300060&KeyUID=WOS:000330017300060}, DOI={10.1021/ac401899u}, abstractNote={Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev.}, number={17}, journal={Analytical Chemistry}, author={Bwambok, David K. and Thuo, Martin M. and Atkinson, Manza B. J. and Mirica, Katherine A. and Shapiro, Nathan D. and Whitesides, George M.}, year={2013}, pages={8442–8447} }
 @article{atkinson_bwambok_chen_chopade_thuo_mace_mirica_kumar_myerson_whitesides_2013, title={Using Magnetic Levitation to Separate Mixtures of Crystal Polymorphs}, volume={52}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000329141800007&KeyUID=WOS:000329141800007}, DOI={10.1002/anie.201305549}, abstractNote={MagLev offers four advantages:1) it separates multiple populations in a single step, 2) itquantifies the density of each population, 3) it is applicable tosmall crystals (100 mm size), and 4) it provides seed crystalsfor large-scale crystallization. We used MagLev to separatemixtures of polymorphs of four compounds: 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY) 1, sulfa-thiazole 2, carbamazepine 3, and trans-cinnamic acid 4(Scheme 1).A survey of the Cambridge Structural Database indicatesthat 3.1–3.5% of the compounds submitted crystallize indifferent polymorphic forms.}, number={39}, journal={Angewandte Chemie-International Edition}, author={Atkinson, Manza B. J. and Bwambok, David K. and Chen, Jie and Chopade, Prashant D. and Thuo, Martin M. and Mace, Charles R. and Mirica, Katherine A. and Kumar, Ashok A. and Myerson, Allan S. and Whitesides, George M.}, year={2013}, pages={10208–10211} }
 @article{atkinson_bwambok_chen_chopade_thuo_mace_mirica_kumar_myerson_whitesides_2013, title={Using Magnetic Levitation to Separate Mixtures of Crystal Polymorphs}, volume={125}, DOI={10.1002/ange.201305549}, abstractNote={Magnetische Levitation (MagLev) ist eine einfache Trennmethode für Kristallpolymorphe mit Dichteunterschieden (Δρ) von nur 0.001 g cm−3. Für vier organische Verbindungen wurden dichtebasierte Trennungen verschiedener kristalliner Formen gezeigt: 5-Methyl-2-[(2-nitrophenyl)amino]-3-thiophencarbonitril, Sulfathiazol, Carbamazepin und trans-Zimtsäure.}, number={39}, journal={Angew. Chem.}, publisher={Wiley-Blackwell}, author={Atkinson, Manza B. J. and Bwambok, David K. and Chen, Jie and Chopade, Prashant D. and Thuo, Martin M. and Mace, Charles R. and Mirica, Katherine A. and Kumar, Ashok A. and Myerson, Allan S. and Whitesides, George M.}, year={2013}, month={Aug}, pages={10398–10401} }
 @article{cademartiri_thuo_nijhuis_reus_tricard_barber_sodhi_brodersen_kim_chiechi_et al._2012, title={Electrical Resistance of Ag-TS-S(CH2)(n-1)CH3//Ga2O3/EGaln Tunneling Junctions}, volume={116}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000304338500003&KeyUID=WOS:000304338500003}, DOI={10.1021/jp212501s}, abstractNote={Tunneling junctions having the structure AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn allow physical–organic studies of charge transport across self-assembled monolayers (SAMs). In ambient conditions, the surface of the liquid metal electrode (EGaIn, 75.5 wt % Ga, 24.5 wt % In, mp 15.7 °C) oxidizes and adsorbs―like other high-energy surfaces―adventitious contaminants. The interface between the EGaIn and the SAM thus includes a film of metal oxide, and probably also organic material adsorbed on this film; this interface will influence the properties and operation of the junctions. A combination of structural, chemical, and electrical characterizations leads to four conclusions about AgTS–S(CH2)n−1CH3//Ga2O3/EGaIn junctions. (i) The oxide is ∼0.7 nm thick on average, is composed mostly of Ga2O3, and appears to be self-limiting in its growth. (ii) The structure and composition (but not necessarily the contact area) of the junctions are conserved from junction to junction. (iii) The transport of charge through the junction...}, number={20}, journal={Journal of Physical Chemistry C}, publisher={American Chemical Society (ACS)}, author={Cademartiri, Ludovico and Thuo, Martin M. and Nijhuis, Christian A. and Reus, William F. and Tricard, Simon and Barber, Jabulani R. and Sodhi, Rana N. S. and Brodersen, Peter and Kim, Choongik and Chiechi, Ryan C. and et al.}, year={2012}, pages={10848–10860} }
 @inproceedings{thuo_reus_simeone_whitesides_2012, title={Physical-organic studies of charge transport across EGaIn-based junctions I: Substituting CH2CH2 with CONH}, booktitle={244th ACS National Meeting}, author={Thuo, M.M. and Reus, W.F. and Simeone, F.C. and Whitesides, G.M.}, year={2012} }
 @inproceedings{thuo_reus_simeone_whitesides_2012, title={Physical-organic studies on the rate of charge transport across EGaIn-based junctions}, booktitle={International Conference of Young Researchers on Advanced Materials}, author={Thuo, M.M. and Reus, W.F. and Simeone, F.C. and Whitesides, G.M.}, year={2012} }
 @article{thuo_reus_simeone_kim_schulz_yoon_whitesides_2012, title={Replacing -CH2CH2- with -CONH- Does Not Significantly Change Rates of Charge Transport through Ag-TS-SAM//Ga2O3/EGaIn Junctions}, volume={134}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000305863900033&KeyUID=WOS:000305863900033}, DOI={10.1021/ja301778s}, abstractNote={This paper describes physical-organic studies of charge transport by tunneling through self-assembled monolayers (SAMs), based on systematic variations of the structure of the molecules constituting the SAM. Replacing a -CH(2)CH(2)- group with a -CONH- group changes the dipole moment and polarizability of a portion of the molecule and has, in principle, the potential to change the rate of charge transport through the SAM. In practice, this substitution produces no significant change in the rate of charge transport across junctions of the structure Ag(TS)-S(CH(2))(m)X(CH(2))(n)H//Ga(2)O(3)/EGaIn (TS = template stripped, X = -CH(2)CH(2)- or -CONH-, and EGaIn = eutectic alloy of gallium and indium). Incorporation of the amide group does, however, increase the yields of working (non-shorting) junctions (when compared to n-alkanethiolates of the same length). These results suggest that synthetic schemes that combine a thiol group on one end of a molecule with a group, R, to be tested, on the other (e.g., HS~CONH~R) using an amide-based coupling provide practical routes to molecules useful in studies of molecular electronics.}, number={26}, journal={Journal of the American Chemical Society}, author={Thuo, Martin M. and Reus, William F. and Simeone, Felice C. and Kim, Choongik and Schulz, Michael D. and Yoon, Hyo Jae and Whitesides, George M.}, year={2012}, pages={10876–10884} }
 @article{reus_nijhuis_barber_thuo_tricard_whitesides_2012, title={Statistical Tools for Analyzing Measurements of Charge Transport}, volume={116}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000301766800026&KeyUID=WOS:000301766800026}, DOI={10.1021/jp210445y}, abstractNote={This paper applies statistical methods to analyze the large, noisy data sets produced in measurements of tunneling current density (J) through self-assembled monolayers (SAMs) in large-area junctions. It describes and compares the accuracy and precision of procedures for summarizing data for individual SAMs, for comparing two or more SAMs, and for determining the parameters of the Simmons model (β and J0). For data that contain significant numbers of outliers (i.e., most measurements of charge transport), commonly used statistical techniquese.g., summarizing data with arithmetic mean and standard deviation and fitting data using a linear, least-squares algorithmare prone to large errors. The paper recommends statistical methods that distinguish between real data and artifacts, subject to the assumption that real data (J) are independent and log-normally distributed. Selecting a precise and accurate (conditional on these assumptions) method yields updated values of β and J0 for charge transport across both odd and even n-alkanethiols (with 99% confidence intervals) and explains that the so-called odd−even effect (for n-alkanethiols on Ag) is largely due to a difference in J0 between odd and even n-alkanethiols. This conclusion is provisional, in that it depends to some extent on the statistical model assumed, and these assumptions must be tested by future experiments.}, number={11}, journal={J. Phys. Chem. C}, author={Reus, William F. and Nijhuis, Christian A. and Barber, Jabulani R. and Thuo, Martin M. and Tricard, Simon and Whitesides, George M.}, year={2012}, pages={6714–6733} }
 @article{yoon_shapiro_park_thuo_soh_whitesides_2012, title={The Rate of Charge Tunneling through Self-Assembled Monolayers Is Insensitive to Many Functional Group Substitutions}, volume={51}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000303506800028&KeyUID=WOS:000303506800028}, DOI={10.1002/anie.201201448}, abstractNote={At its conception, the field of molecular electronics promised to provide the ability to engineer the rate of charge transport, by design of the molecular structure of electronic junctions.[1] The hypothesis was that the electronic and geometrical structure of molecules in a junction would have a significant and predictable effect on the rate and mechanism of charge transport through their influence on the energetic topography of the tunneling barrier. Here we show the preparation and electrical characterization of junctions (Figure 1) of the structure AgTS/S(CH2)4CONH(CH2)2R//Ga2O3/EGaIn (AgTS = template-stripped silver surface[2]; R = tail group; EGaIn = eutectic gallium and indium alloy; Ga2O3 = a passivating metal oxide film on the surface of the EGaIn[3–5]) including a range of common aliphatic, aromatic, and heteroaromatic organic tail groups. We demonstrate that the rate of charge transport across these self-assembled monolayers (SAMs) is surprisingly insensitive to changes in the structure of the organic molecules of which they are composed. This study is based on a physical-organic design: that is, the information it provides comes from comparisons of rates of tunneling across related structures, rather than from the interpretation of the absolute values of single measurements. 
 
 
 
Figure 1 
 
A) Schematic description of tunneling junction consisting of a template-stripped Ag bottom-electrode supporting a SAM, and contacted by a Ga2O3/EGaIn top-electrode. B) A schematic of one junction. C) The numbering system based on non-hydrogen atoms in ... 
 
 
 
Targets for shaping the tunneling barriers of molecular junctions have included electron–donor–bridge–acceptor molecules,[1a,6] molecular quantum dot systems,[7] aromatic molecules,[8] and complex organic molecules with multiple functional groups.[9] Many of these studies ostensibly shaping the tunneling barriers of molecular junctions have, however, been difficult to interpret because, when they were carried out, there were no experimental systems that generated well-characterized, statistically validated data. This paper characterizes the rates of charge transport by tunneling across a series of molecules—arrayed in SAMs—containing a common head group and body (HS(CH2)4CONH(CH2)2-) and structurally varied tail groups (-R); these molecules are assembled in junctions of the structure AgTS/SAM//Ga2O3/EGaIn. Over a range of common aliphatic, aromatic, and heteroaromatic organic tail groups, changing the structure of R does not significantly influence the rate of tunneling. In making these measurements, we utilize C12 and C18 alkanethiols as calibration standards to allow comparison with results from other types of junctions. 
 
Limited studies[4,5,10–15] of charge transport using a range of junctions have described the relation between molecular structure and the rate of tunneling. For example, Venkataraman et al.[14] reported that the rate of charge transport through a series of diaminobenzenes depends on the alignment of the metal Fermi level to the closest molecular orbital. Chiechi and Solomon et al.[15] compared the rate of charge transport through three different anthracene derivatives of approximately the same thickness, and concluded that conjugation influences the rate of charge transport. Studies exploring the correlation between molecular structure and charge transport based on systematic physical–organic measurements of the rate of charge transport over a wide range of structures are sparse. This paper describes tunneling rates through SAMs of molecules with a variety of molecular structures including aromatic, heterocyclic, and aliphatic moieties. We have previously examined ferrocene-terminated SAMs[4] and SAMs comprising odd-and even-numbered n-alkanethiolates.[5]}, number={19}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Yoon, Hyo Jae and Shapiro, Nathan D. and Park, Kyeng Min and Thuo, Martin M. and Soh, Siowling and Whitesides, George M.}, year={2012}, pages={4658–4661} }
 @article{reus_thuo_shapiro_nijhuis_whitesides_2012, title={The SAM, Not the Electrodes, Dominates Charge Transport in Metal-Monolayer//Ga2O3/Gallium-Indium Eutectic Junctions}, volume={6}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000305661300028&KeyUID=WOS:000305661300028}, DOI={10.1021/nn205089u}, abstractNote={The liquid-metal eutectic of gallium and indium (EGaIn) is a useful electrode for making soft electrical contacts to self-assembled monolayers (SAMs). This electrode has, however, one feature whose effect on charge transport has been incompletely understood: a thin (approximately 0.7 nm) film-consisting primarily of Ga(2)O(3)-that covers its surface when in contact with air. SAMs that rectify current have been measured using this electrode in Ag(TS)-SAM//Ga(2)O(3)/EGaIn (where Ag(TS) = template-stripped Ag surface) junctions. This paper organizes evidence, both published and unpublished, showing that the molecular structure of the SAM (specifically, the presence of an accessible molecular orbital asymmetrically located within the SAM), not the difference between the electrodes or the characteristics of the Ga(2)O(3) film, causes the observed rectification. By examining and ruling out potential mechanisms of rectification that rely either on the Ga(2)O(3) film or on the asymmetry of the electrodes, this paper demonstrates that the structure of the SAM dominates charge transport through Ag(TS)-SAM//Ga(2)O(3)/EGaIn junctions, and that the electrical characteristics of the Ga(2)O(3) film have a negligible effect on these measurements.}, number={6}, journal={Acs Nano}, author={Reus, William F. and Thuo, Martin M. and Shapiro, Nathan D. and Nijhuis, Christian A. and Whitesides, George M.}, year={2012}, pages={4806–4822} }
 @article{atkinson_sokolov_bucar_mariappan_mwangi_tiedman_macgillivray_2011, title={Applications of hydrogen-bond-acceptor templates to direct in-phase' reactivity of a diene diacid in the solid state}, volume={10}, DOI={10.1039/c1pp05077j}, abstractNote={The hydrogen-bond-acceptor (HBA) templates 2,3-bis(4-methylenethiopyridyl)naphthalene (2,3-nap) and 1,8-bis(4- pyridyl)naphthalene (1,8-dpn) are used to assemble ( E,E )-2,5-dimethylmuconic acid (dmma) in the solid state for an intermolecular [2 + 2] photocycloaddition. Co-crystallisation of 2,3-nap with dmma affords an 1D hydrogen-bonded polymer that is photostable while 1,8-nap affords a 0D hydrogen-bonded assembly that is photoactive. The diene stacks in-phase and reacts to give a syn monocyclobutane in up to 55% yield.}, number={9}, journal={Photochem. Photobiol. Sci.}, author={Atkinson, Manza B. J. and Sokolov, Anatoliy N. and Bucar, Dejan-Kresimir and Mariappan, S. V. Santhana and Mwangi, Martin T. and Tiedman, Michael C. and MacGillivray, Leonard R.}, year={2011}, pages={1384–1386} }
 @article{derda_tang_laromaine_mosadegh_hong_mwangi_mammoto_ingber_whitesides_2011, title={Multizone Paper Platform for 3D Cell Cultures}, volume={6}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000290305600010&KeyUID=WOS:000290305600010}, DOI={e18940
10.1371/journal.pone.0018940}, number={5}, journal={Plos One}, author={Derda, Ratmir and Tang, Sindy K. Y. and Laromaine, Anna and Mosadegh, Bobak and Hong, Estrella and Mwangi, Martin and Mammoto, Akiko and Ingber, Donald E. and Whitesides, George M.}, year={2011} }
 @article{thuo_reus_nijhuis_barber_kim_schulz_whitesides_2011, title={Odd-Even Effects in Charge Transport across Self-Assembled Monolayers}, volume={133}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000289455200033&KeyUID=WOS:000289455200033}, DOI={10.1021/ja1090436}, abstractNote={This paper compares charge transport across self-assembled monolayers (SAMs) of n-alkanethiols containing odd and even numbers of methylenes. Ultraflat template-stripped silver (Ag(TS)) surfaces support the SAMs, while top electrodes of eutectic gallium-indium (EGaIn) contact the SAMs to form metal/SAM//oxide/EGaIn junctions. The EGaIn spontaneously reacts with ambient oxygen to form a thin (∼1 nm) oxide layer. This oxide layer enables EGaIn to maintain a stable, conical shape (convenient for forming microcontacts to SAMs) while retaining the ability to deform and flow upon contacting a hard surface. Conical electrodes of EGaIn conform (at least partially) to SAMs and generate high yields of working junctions. Ga(2)O(3)/EGaIn top electrodes enable the collection of statistically significant numbers of data in convenient periods of time. The observed difference in charge transport between n-alkanethiols with odd and even numbers of methylenes--the "odd-even effect"--is statistically discernible using these junctions and demonstrates that this technique is sensitive to small differences in the structure and properties of the SAM. Alkanethiols with an even number of methylenes exhibit the expected exponential decrease in current density, J, with increasing chain length, as do alkanethiols with an odd number of methylenes. This trend disappears, however, when the two data sets are analyzed together: alkanethiols with an even number of methylenes typically show higher J than homologous alkanethiols with an odd number of methylenes. The precision of the present measurements and the statistical power of the present analysis are only sufficient to identify, with statistical confidence, the difference between an odd and even number of methylenes with respect to J, but not with respect to the tunneling decay constant, β, or the pre-exponential factor, J(0). This paper includes a discussion of the possible origins of the odd-even effect but does not endorse a single explanation.}, number={9}, journal={Journal of the American Chemical Society}, author={Thuo, Martin M. and Reus, William F. and Nijhuis, Christian A. and Barber, Jabulani R. and Kim, Choongik and Schulz, Michael D. and Whitesides, George M.}, year={2011}, pages={2962–2975} }
 @inproceedings{liu_o'brien_mwangi_li_whitesides_2011, title={Paper-based piezoresistive MEMS force sensors}, url={http://dx.doi.org/10.1109/memsys.2011.5734379}, DOI={10.1109/memsys.2011.5734379}, abstractNote={This paper describes the development of piezoresistive MEMS force sensors constructed using paper as the structural material. The sensing principle of the paper-based sensor is based on the piezoresistive effect of conductive materials patterned on a paper substrate. The device is inexpensive (∼$0.04/device for materials), simple to fabricate, lightweight, and disposable. The entire fabrication process can be completed within one hour in common laboratories with simple tools (e.g., a paper cutter and a painting knife), without requiring cleanroom facilities. The paper substrate allows easy integration of electrical signal processing circuits onto the paper-based MEMS devices. We demonstrated that the paper-based sensor can measure forces with moderate performance (i.e., detection limit: 120 µN, measurement range: ±16 mN, and sensitivity: 0.84 mV/mN), and applied the sensor to characterizing mechanical properties of soft materials. We also developed a paper-based weighting balance with a measurement range of 15 g and a resolution of 25 mg.}, booktitle={2011 IEEE 24th International Conference on Micro Electro Mechanical Systems}, publisher={IEEE}, author={Liu, X.Y. and O'Brien, M. and Mwangi, M. and Li, X.J. and Whitesides, G.M.}, year={2011}, month={Jan}, pages={133–136} }
 @article{liu_mwangi_li_o’brien_whitesides_2011, title={Paper-based piezoresistive MEMS sensors}, volume={11}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000291555500009&KeyUID=WOS:000291555500009}, DOI={10.1039/c1lc20161a}, abstractNote={This paper describes the development of MEMS force sensors constructed using paper as the structural material. The working principle on which these paper-based sensors are based is the piezoresistive effect generated by conductive materials patterned on a paper substrate. The device is inexpensive (∼$0.04 per device for materials), simple to fabricate, lightweight, and disposable. Paper can be readily folded into three-dimensional structures to increase the stiffness of the sensor while keeping it light in weight. The entire fabrication process can be completed within one hour without expensive cleanroom facilities using simple tools (e.g., a paper cutter and a painting knife). We demonstrated that the paper-based sensor can measure forces with moderate performance (i.e., resolution: 120 μN, measurement range: ±16 mN, and sensitivity: 0.84 mV mN(-1)). We applied this sensor to characterizing the mechanical properties of a soft material. Leveraging the same sensing concept, we also developed a paper-based balance with a measurement range of 15 g, and a resolution of 0.39 g.}, number={13}, journal={Lab on a Chip}, author={Liu, Xinyu and Mwangi, Martin and Li, XiuJun and O’Brien, Michael and Whitesides, George M.}, year={2011}, pages={2189–2196} }
 @inproceedings{mwangi_reus_kim_schulz_whitesides_2010, title={Improving the yield of working tunnel junctions (AgTS/SAM//oxide/EGaIn) through near-surface effects on the SAM}, booktitle={240th ACS National Meeting}, author={Mwangi, M.T. and Reus, W. and Kim, C. and Schulz, M.D. and Whitesides, G.M.}, year={2010} }
 @inproceedings{mwangi_reus_nijhuis_kim_barber_whitesides_2010, title={Odd-even effects in tunneling across n-alkanethiols self-assembled monolayers}, booktitle={Gordon Conference}, author={Mwangi, M.T. and Reus, W. and Nijhuis, C. and Kim, C. and Barber, J. and Whitesides, G.M.}, year={2010} }
 @inproceedings{mwangi_reus_nijhuis_kim_barber_schulz_whitesides_2010, title={Odd-even effects on charge transport across n-alkanethiolate SAMs on metal/SAM/oxide/EGaIn junction}, booktitle={Abstracts of Papers, 240th ACS National Meeting}, author={Mwangi, M.T. and Reus, W. and Nijhuis, C. and Kim, C. and Barber, J. and Schulz, M.D. and Whitesides, G.M.}, year={2010} }
 @inproceedings{mwangi_runge_hoak_schulz_elsey_beaubrun_bowden_2009, title={"Pot-in-pot" reactions: A new paradigm in “Ad infinitum” cascade reactions}, booktitle={13th ACS green Chemistry Conference}, author={Mwangi, M.T. and Runge, M.B. and Hoak, K.M. and Schulz, M.D. and Elsey, R.J. and Beaubrun, A.C. and Bowden, N.B.}, year={2009} }
 @book{runge_thuo mwangi_miller_perring_hoak_schulz_bowden_2009, title={PDSM thimbles for the development of cascade reactions: A materials approach to organic chemistry}, journal={Polymeric Materials Science and Engineering (PMSE) preprints}, author={Runge, M.B. and Thuo Mwangi, M. and Miller, A.L., II and Perring, M. and Hoak, Kevin M. and Schulz, M.D. and Bowden, N.B.}, year={2009} }
 @article{mwangi_schulz_bowden_2009, title={Sequential Reactions with Grubbs Catalyst and AD-mix-α/β Using PDMS Thimbles}, volume={11}, ISSN={1523-7060 1523-7052}, url={http://dx.doi.org/10.1021/ol8022215}, DOI={10.1021/ol8022215}, abstractNote={Incompatible Grubbs catalyst and an osmium dihydroxylation catalyst were site-isolated from each other using polydimethylsiloxane thimbles. The Grubbs catalyst was added to the interior of the thimbles, and AD-mix-alpha/beta was added to the exterior. Organic substrates readily fluxed through the walls of the thimbles and reacted with each catalyst. A series of cascade reactions were developed including those with intermediates possessing low boiling points or that were foul smelling.}, number={1}, journal={Organic Letters}, publisher={American Chemical Society (ACS)}, author={Mwangi, Martin T. and Schulz, Michael D. and Bowden, Ned B.}, year={2009}, pages={33–36} }
 @inproceedings{mwangi_runge_bowden_2008, title={"Pot-in-pot" reactions: Polymers macro- fabrication for site-isolation of catalysts and reagents}, booktitle={AIChE Spring National Meeting}, author={Mwangi, M.T. and Runge, M.B. and Bowden, N.B.}, year={2008} }
 @inproceedings{mwangi_runge_bowden_2008, title={"Pot-in-pot" reactions: Site-isolation of organometallic catalysts from each other for versatile cascade reactions and catalyst recycling}, booktitle={235th ACS National Meeting}, author={Mwangi, M.T. and Runge, M.B. and Bowden, N.B.}, year={2008} }
 @article{mwangi_runge_hoak_schulz_bowden_2008, title={A materials approach to site-isolation of Grubbs catalysts from incompatible solvents and m-chloroperoxybenzoic acid}, volume={14}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000258217000025&KeyUID=WOS:000258217000025}, DOI={10.1002/chem.200800094}, abstractNote={The development of a method for site-isolation of Grubbs second-generation catalyst from MCPBA is described. In these reactions, Grubbs catalyst was dissolved in a solvent consisting of a mixture (1:1 v/v) of 1-butyl-3-methylimidazolium hexafluorophosphate and methylene chloride and completely encapsulated within a thimble fabricated from polydimethylsiloxane (PDMS). A series of molecules that react by cross metathesis or ring-closing metathesis were added to the interior of the thimble and allowed to react. In the last step, m-chloroperoxybenzoic acid (MCPBA) dissolved in MeOH/H(2)O (1:1 v/v) was added to the exterior of the PDMS thimble. Small organic molecules diffused through the PDMS to react with MCPBA to form epoxides, but the Grubbs catalyst remained encapsulated. This result is important because Grubbs catalyst catalytically decomposes MCPBA at ratios of MCPBA to Grubbs of 3000 to 1. The yields for this two-step cascade sequence ranged from 67 to 83 %. The concept behind this sequence is that small organic molecules have high flux through PDMS but large molecules--such as Grubbs catalyst--and ionic reagents--such as MCPBA--have much lower flux through PDMS. Small molecules can thus react both outside and inside PDMS thimbles, whereas incompatible catalysts and reagents remain site-isolated from each other. This method does not require alteration of structures of the catalysts or reagents, so it may be applied to a wide range of homogeneous catalysts and reagents. To demonstrate further that the catalyst was encapsulated, the Grubbs catalyst was successfully recycled within the cascade sequence.}, number={22}, journal={Chem. - Eur. J.}, author={Mwangi, Martin T. and Runge, M. Brett and Hoak, Kevin M. and Schulz, Michael D. and Bowden, Ned B.}, year={2008}, pages={6780–6788} }
 @article{runge_mwangi_miller_perring_bowden_2008, title={Cascade reactions using LiAlH4 and Grignard reagents in the presence of water}, volume={47}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000252651200024&KeyUID=WOS:000252651200024}, DOI={10.1002/anie.200703002}, abstractNote={The development of cascade reactions—often called domino, tandem, or multicomponent reactions—is a major challenge in chemistry because of the difficulties in carrying out multiple reactions in one vessel. These reactions are attractive goals because they save time and materials while producing less waste than the tradition method of carrying out reactions one at a time followed by purification and characterization of each product. In cascade reactions, two or more reactions are carried out in one reaction vessel so the number of purification and characterization steps are lowered which speeds up the synthesis. These reactions have the potential to change how molecules are synthesized in academic and industrial laboratories. For example, the synthesis of one kilogram of a pharmaceutical product typically yields 25 to 100 kilograms of waste; this amount of waste could be lowered through the use of cascade reactions. Most methods to carry out cascade reactions use one catalyst that is responsible for catalyzing two or more reactions. Although highly successful when discovered, these reactions fail to use many of the catalysts and reagents that have been reported that are successful for one reaction but are not readily integrated into cascade sequences. An important frontier in this field is to develop methods to use multiple, commercially available catalysts or reagents in cascade reactions to increase the complexity of products that can be produced. The key problem with cascade reactions that use multiple catalysts or reagents is that these components often poison each other. A solution to this problem is to site-isolate catalysts and reagents from each other such that they do not come into contact and poison one another. Site-isolation is typically carried out by bonding a catalyst to a polymer support, a heterogeneous surface, or encapsulating it within a sol–gel or zeolite. For instance, in recent work Hawker, Fr1chet, and co-workers attached acidic and basic residues to the interior of star polymers such that they did not quench each other, which allowed both acidand base-catalyzed reactions in the same reaction vessel. Site-isolation has challenges and limitations because it often requires additional synthetic steps and changes both the structure and activity of catalysts or reagents. In addition, the site-isolation of many reagents is challenging because all or part of their structures are integrated into the final product, thus affecting their structures to bond them to a support alters the final product. In addition, many reagents, such as water, LiAlH4, and Grignard reagents, are commonly found in organic chemistry and are inexpensive, but they are not easily site-isolated. For instance, water and LiAlH4 rapidly react with one another and can not be added to the same reaction vessel. Herein we will describe a general method to site-isolate water from LiAlH4, Grignard, or cuprate reagents to carry out a series of cascade reactions using these reagents. Our method for site-isolation of water from LiAlH4 and Grignard reagents uses polydimethylsiloxane (PDMS) thimbles to completely encapsulate water (Figure 1). PDMS is a}, number={5}, journal={Angew. Chem., Int. Ed.}, author={Runge, M. Brett and Mwangi, Marin T. and Miller, A. Lee, II and Perring, Mathew and Bowden, Ned B.}, year={2008}, pages={935–939} }
 @article{mwangi_thuo_gikonyo_ndiege_2008, title={Repellent Properties of δ-Octalactone Against the Tsetse Fly, <i>Glossina morsitans Morsitans}, volume={8}, ISSN={1536-2442}, url={http://dx.doi.org/10.1673/031.008.4301}, DOI={10.1673/031.008.4301}, abstractNote={Delta-octalactone, produced by several Bovidae, has been suggested as a potential repellant of tsetse fly attack. Racemic delta-octalactone was synthesized via an abbreviated route. The product was assayed against 3-day old starved teneral female tsetse flies, Glossina morsitans morsitans Wiedemann (Diptera: Glossinidae), in a choice wind tunnel and found to be a potent tsetse repellent at doses >or=0.05 mg in 200 microl of paraffin oil (0.05 >p >0.01).}, number={1}, journal={Journal of Insect Science}, publisher={Oxford University Press (OUP)}, author={Mwangi, M. and Thuo, M. and Gikonyo, Nicholas K. and Ndiege, Isaiah O.}, year={2008}, month={May}, pages={43} }
 @inproceedings{mwangi_runge_hoak_bowden_2007, title={A new approach to cascade reactions using site-isolated catalyst and/or reagents}, booktitle={8th International Symposium on Carbanion Chemistry}, author={Mwangi, M.T. and Runge, M.B. and Hoak, K.M. and Bowden, N.B.}, year={2007} }
 @inproceedings{mwangi_runge_bowden_2007, title={Occlusion of Grubbs' metathesis catalysts in PDMS: Serendipitous discovery of new reactivities in aqueous solvents}, booktitle={233rd ACS National Meeting}, author={Mwangi, M.T. and Runge, M.B. and Bowden, N.B.}, year={2007} }
 @article{runge_mwangi_bowden_2006, title={New selectivities from old catalysts. Occlusion of Grubbs' catalysts in PDMS to change their reactions}, volume={691}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000243267200021&KeyUID=WOS:000243267200021}, DOI={10.1016/j.jorganchem.2006.09.022}, abstractNote={This article describes new selectivities for Grubbs’ first and second generation catalysts when occluded in a hydrophobic matrix of polydimethylsiloxane (PDMS). Occlusion of catalysts in mm-sized slabs of PDMS is accomplished by swelling with methylene chloride then removing the solvent under vacuum. The catalysts are homogenously dissolved in PDMS yet remain catalytically active. Many substrates that react by olefin metathesis with Grubbs’ catalysts freely dissolved in methylene chloride also react by olefin isomerization with occluded catalysts. Eleven examples of substrates that exhibit dual reactivity by undergoing olefin isomerization with occluded catalysts and olefin metathesis with catalysts dissolved in methylene chloride are reported. Most of these substrates have olefins with allylic phosphine oxides, carbonyls, or ethers. Control experiments demonstrate that isomerization is occurring in the solvent by decomposition of the catalyst from a ruthenium carbene to a proposed ruthenium hydride. This work was extended by heating occluded Grubbs’ first generation catalyst to 100 °C in 90% MeOH in H2O in the presence of various alkenes to transform the Grubbs’ catalyst into an isomerization catalyst for unfunctionalized olefins. This work demonstrates that occlusion of organometallic catalysts in PDMS has important implications for their reactions and can be used as a method to control which reactions they catalyze.}, number={24-25}, journal={JOURNAL OF ORGANOMETALLIC CHEMISTRY}, author={RUNGE, MB and MWANGI, MT and BOWDEN, NB}, year={2006}, pages={5278–5288} }
 @article{mwangi_runge_bowden_2006, title={Occlusion of Grubbs' catalysts in active membranes of polydimethylsiloxane: Catalysis in water and new functional group selectivities}, volume={128}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000241857200009&KeyUID=WOS:000241857200009}, DOI={10.1021/ja0642212}, abstractNote={The Grubbs' first and second generation catalysts were occluded into cross-linked slabs of polydimethylsiloxane with volumes from 1 mm3 to 1 cm3 by swelling the polymer with catalyst and methylene chloride. Methylene chloride was evaporated under vacuum to yield occluded catalysts where their solvent was polydimethylsiloxane. These occluded catalysts were reacted with alkenes dissolved in H2O or H2O/MeOH mixtures that diffused into the polydimethylsiloxane to react by ring-closing metathesis and cross metathesis. Control experiments revealed that the catalysts remained occluded and metathesis did not occur in the solvent. Occlusion of these catalysts allowed commercially available Grubbs' catalysts to be used with H2O as the solvent while isolating the H2O sensitive ruthenium methylidene from exposure to H2O. Functional group selective experiments were carried out where the polydimethylsiloxane was an "active" membrane to exclude salts. Polydimethylsiloxane is a hydrophobic polymer, so the deprotonated salt of diallylmalonic acid did not diffuse into it while a diallylether diffused into it and reacted by metathesis. Thus, by controlling the polarity of reagents their reactivity can be controlled owing to the properties of polydimethylsiloxane rather than those of the Grubbs' catalysts. Occlusion of catalysts in polydimethylsiloxane has been shown to add new selectivities to mature catalysts.}, number={45}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={MWANGI, MT and RUNGE, MB and BOWDEN, NB}, year={2006}, pages={14434–14435} }
 @article{plettner_mohle_mwangi_griscti_patrick_nair_batchelor_einstein_2005, title={2-Chlorobicyclo[2.2.1]hept-5-ene-2-carboxamide and 2-chlorobicyclo[2.2.1]heptane-2-carboxamide as precursors of bicyclo[2.2.1]hept-5-en-2-one and bicyclo[2.2.1]heptan-2-one: resolution, absolute configuration and hydrogen-bonding properties}, volume={16}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000231719800010&KeyUID=WOS:000231719800010}, DOI={10.1016/j.tetasy.2005.07.016}, abstractNote={The absolute configuration of bicyclo[2.2.1]heptan-2-one has not been correlated with a crystal structure of a chemical precursor. The only chemical correlation available had an ambiguity, which could have reversed the assignment. Herein, we report the resolution of 2-chlorobicyclo[2.2.1]hept-5-en-2-exo-carboxamide on a cellulose triacetate column and the crystal structures of the enantiomerically pure and racemic α-chloroamide. We found the absolute configuration (1R,2R,4R) for the (+)-enantiomer of the α-chloroamide. This compound was converted to (+)-bicyclo[2.2.1]hept-5-ene-2-one by base hydrolysis, and the 5,6-unsaturated compounds converted to the saturated congeners. This is the first unambiguous experimental determination of the absolute configuration of bicyclo[2.2.1]heptan-2-one and of bicyclo[2.2.1]hept-5-ene-2-one. The three crystal structures of 2-chlorobicyclo[2.2.1]hept-5-en-2-exo-carboxamide reported herein reveal H-bonded dimers, with two distinct orientations of the bicyclic portion relative to the carboxamide dimer. In the racemic crystal, each dimer is composed of two enantiomers, and the bicyclic portions have their bridge carbon atom (C-7) on opposite sides of the H-bonded carboxamide dimer moiety. In the enantiomerically pure crystals, the major dimer had both C-7 atoms on the same side of the carboxamide dimer moiety while the minor dimer had the C-7 atoms on opposite sides. The dimers are present in solution, and can be easily monitored.}, number={16}, journal={TETRAHEDRON-ASYMMETRY}, author={PLETTNER, E and MOHLE, A and MWANGI, MT and GRISCTI, J and PATRICK, BO and NAIR, R and BATCHELOR, RJ and EINSTEIN, F}, year={2005}, pages={2754–2763} }