@misc{bain_turgman-cohen_genzer_2013, title={Progress in Computer Simulation of Bulk, Confined, and Surface-initiated Polymerizations}, volume={22}, ISSN={["1521-3919"]}, DOI={10.1002/mats.201200030}, abstractNote={In this article we provide a brief summary of computational techniques applied to investigate polymerization reactions in general, with a focus on systems under confinement and initiated from surfaces. We concentrate on two major classes of techniques, i.e., stochastic methods and molecular modeling. We describe the major principles of the two classes of methodologies and point out their strengths and weaknesses. We review a variety of studies from the literature and conclude with an outlook of these two classes of computer simulation approaches as they are applied to ‘‘grafting from’’ polymerizations.}, number={1}, journal={MACROMOLECULAR THEORY AND SIMULATIONS}, author={Bain, Erich D. and Turgman-Cohen, Salomon and Genzer, Jan}, year={2013}, month={Jan}, pages={8–30} }
 @article{turgman-cohen_genzer_2012, title={Computer Simulation of Concurrent Bulk- and Surface-Initiated Living Polymerization}, volume={45}, ISSN={["0024-9297"]}, DOI={10.1021/ma202679r}, abstractNote={We use Monte Carlo simulation implementing the bond fluctuation model formalism in the canonical (NVT) ensemble to study living polymerization initiated concurrently in bulk and on flat substrates. Our results reveal that the molecular weights and molecular weight distributions of both classes of polymers depend on the grafting density of the surface-bound polymers (σ) and the fraction of polymers on the surface (η) relative to that in bulk. In general, polymer grafts on the surface possess lower molecular weight and higher polydispersity index compared to their bulk counterparts. The difference between the molecular weight of the two populations of polymers decreases with decreasing σ and increasing η. Our work provides evidence that the common practice of using the molecular weight of bulk-initiated polymers in estimating the grafting density of polymeric anchors on flat substrates is not generally valid.}, number={4}, journal={MACROMOLECULES}, author={Turgman-Cohen, Salomon and Genzer, Jan}, year={2012}, month={Feb}, pages={2128–2137} }
 @article{turgman-cohen_genzer_2011, title={Simultaneous Bulk- and Surface-Initiated Controlled Radical Polymerization from Planar Substrates}, volume={133}, ISSN={["0002-7863"]}, DOI={10.1021/ja2081636}, abstractNote={We employ Monte Carlo computer simulations to investigate the simultaneous controlled radical polymerization in solution and from a flat surface. The bulk polymers grow at faster rates and possess narrower molecular weight distribution than polymers initiated from flat, impenetrable surfaces. The rate of surface-initiated polymerization depends on the density of initiator sites. Our results provide evidence that the assumption that the molecular weight of surface-initiated polymers is equal to that of polymers grown in bulk, invoked often in determining the grafting density of surface-bound polymers, is generally invalid.}, number={44}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Turgman-Cohen, Salomon and Genzer, Jan}, year={2011}, month={Nov}, pages={17567–17569} }
 @article{liu_wu_turgman-cohen_genzer_theyson_rojas_2010, title={Adsorption of a Nonionic Symmetric Triblock Copolymer on Surfaces with Different Hydrophobicity}, volume={26}, ISSN={["0743-7463"]}, DOI={10.1021/la100156a}, abstractNote={This study investigates the adsorption of a symmetric triblock nonionic polymer comprising ethylene oxide (EO) and propylene oxide (PO) blocks (Pluronic P-105, EO(37)PO(56)EO(37)) on a range of substrates including hydrophobic, i.e., polypropylene (PP), poly(ethylene terephthalate) (PET), nylon, and graphite, and hydrophilic, i.e., cellulose and silica. The adsorption process and the structure of the hydrated adsorbed layers are followed by quartz crystal microgravimetry (QCM), surface plasmon resonance (SPR), and atomic force microscopy. The unhydrated surfaces are characterized by ellipsometry and contact angle techniques. The adsorption kinetics and the extent of adsorption are determined by monitoring the changes in resonance frequency and refractive index of sensors coated with ultrathin films of the various substrates. Langmuirian-type adsorption kinetics is observed in all cases studied. The amount of adsorbed Pluronic on hydrophobic polymer surfaces (PP, PET, and nylon) exceeds that on the hydrophilic cellulose. The hydrophobic (graphite) mineral surface adsorbs relatively low polymer mass, typical of a monolayer, while micellar structures are observed on the hydrophilic silica surface. The amount of water coupled to the adsorbed polymer layers is quantified by combining data from QCM, and SPR are found to increase with increasing polarity of the substrate. On the basis of contact angle data, the nonhydrated adsorbed structures produce modest increases in hydrophilicity of all the substrates investigated. Overall, insights are provided into the structure and stability of both hydrated and nonhydrated adsorbed triblock copolymer.}, number={12}, journal={LANGMUIR}, author={Liu, Xiaomeng and Wu, Dong and Turgman-Cohen, Salomon and Genzer, Jan and Theyson, Thomas W. and Rojas, Orlando J.}, year={2010}, month={Jun}, pages={9565–9574} }
 @article{turgman-cohen_genzer_2010, title={Computer Simulation of Controlled Radical Polymerization Effect of Chain Confinement Due to Initiator Grafting Density and Solvent Quality in "Grafting From" Method}, volume={43}, ISSN={["1520-5835"]}, DOI={10.1021/ma102046q}, abstractNote={We use stochastic Monte Carlo simulation following the bond fluctuation model to study the effects of grafting density of surface-anchored initiators and solvent quality on controlled radical polymerization (CRP) from flat impenetrable substrates under good and poor solvent conditions. Our CRP model includes a mechanism for activation/deactivation of the chains and neglects termination and chain transfer reactions. The system is, thus, “truly living”. We find that under these conditions, surface-initiated polymerizations at low grafting densities resemble those in the bulk. In contrast, at high initiator grafting densities, these surface-initiated polymerizations result in gradients of the free monomer and chain-end concentrations, which lead to an uneven growth of the chains and ultimately yield polymers with broad molecular weight distributions. Poor solvent conditions exacerbate this problem by collapsing the chains and in some cases forming chain aggregates, which further restrict the access of free m...}, number={22}, journal={MACROMOLECULES}, author={Turgman-Cohen, Salomon and Genzer, Jan}, year={2010}, month={Nov}, pages={9567–9577} }
 @article{dong_turgman-cohen_roberts_kiserow_2010, title={Effect of Polymer Size on Heterogeneous Catalytic Polystyrene Hydrogenation}, volume={49}, ISSN={["0888-5885"]}, DOI={10.1021/ie1011905}, abstractNote={The effect of polymer coil size on the rate of polystyrene (PS) hydrogenation was studied in a slurry reactor with mixtures of decahydronaphthalene (DHN) and carbon dioxide (CO2) as the solvent for the polymer. The PS coil size was changed by varying the polymer molecular weight from 9300 g/mol to 357 000 g/mol and by varying the CO2 concentration. Using a 5% Pd/5% Ru/SiO2 catalyst, the rate of aromatic ring hydrogenation at 150 °C was found to be strongly dependent on the size of a polymer coil relative to the average pore diameter of the catalyst. Significant pore diffusion limitations, as indicated by values of the Weisz modulus, were observed with increasing polymer molecular weight. Increasing the concentration of CO2 resulted in increased reaction rates, with an improvement of nearly 2 orders of magnitude at the highest PS molecular weight.}, number={22}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Dong, Laura Beth and Turgman-Cohen, Salomon and Roberts, George W. and Kiserow, Douglas J.}, year={2010}, month={Nov}, pages={11280–11286} }
 @article{turgman-cohen_fischer_kilpatrick_genzer_2009, title={Asphaltene Adsorption onto Self-Assembled Monolayers of Alkyltrichlorosilanes of Varying Chain Length}, volume={1}, ISSN={["1944-8244"]}, DOI={10.1021/am900203u}, abstractNote={The adsorption of asphaltenes onto flat silica surfaces modified with self-assembled monolayers (SAMs) of alkyltrichlorosilanes of varying thickness due to a variable number of carbon atoms (N(C)) has been studied by means of contact angle measurements, spectroscopic ellipsometry, and near-edge X-ray absorption fine structure spectroscopy. The extent of asphaltene adsorption was found to depend primarily on the ability of the SAM layer to shield the underlying silicon substrate from interacting with the asphaltenes present in solution. Specifically, asphaltene adsorption decreased with an increase in N(C) and/or an increase in SAM grafting density, sigma(SAM), (i.e., number of SAM molecules per unit area). The effect of the solvent quality on the extent of asphaltene adsorption was gauged by adsorbing asphaltenes from toluene, 1-methylnaphthalene, tetralin, decalin, and toluene-heptanes mixtures. The extent of asphaltene adsorption was found to increase proportionally with a decrease in the Hildebrand solubility parameter of the solvent.}, number={6}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Turgman-Cohen, Salomon and Fischer, Daniel A. and Kilpatrick, Peter K. and Genzer, Jan}, year={2009}, month={Jun}, pages={1347–1357} }
 @article{turgman-cohen_smith_fischer_kilpatrick_genzer_2009, title={Asphaltene Adsorption onto Self-Assembled Monolayers of Mixed Aromatic and Aliphatic Trichlorosilanes}, volume={25}, ISSN={["0743-7463"]}, DOI={10.1021/la9000895}, abstractNote={The adsorption of asphaltenes onto flat solid surfaces modified with mixed self-assembled monolayers (SAMs) of aliphatic and aromatic trichlorosilanes with varying wettabilities, aromaticities, and thicknesses is tested. The mixed SAMs are characterized by means of contact angle to assess hydrophobicity and molecular and chemical uniformity, spectroscopic ellipsometry to measure the thickness of the films, and near edge X-ray absorption fine structure (NEXAFS) spectroscopy to assess chemical and molecular composition. The molecular characteristics of the adsorbed asphaltene layer and the extent of asphaltene adsorption are determined using NEXAFS and spectroscopic ellipsometry, respectively. The SAMs are formed by depositing phenyl-, phenethyl-, butyl-, and octadecyl- trichlorosilanes from toluene solutions onto silica-coated substrates; the chemical composition and the wettability of the SAM surface is tuned systematically by varying the trichlorosilane composition in the deposition solutions. The adsorption of asphaltenes on the substrates does not correlate strongly with the SAM chemical composition. Instead, the extent of asphaltene adsorption decreases with increasing SAM thickness. This observation suggests that the leading interaction governing the adsorption of asphaltenes is their interaction with the polar silica substrate and that the chemical composition of the SAM is of secondary importance.}, number={11}, journal={LANGMUIR}, author={Turgman-Cohen, Salomon and Smith, Matthew B. and Fischer, Daniel A. and Kilpatrick, Peter K. and Genzer, Jan}, year={2009}, month={Jun}, pages={6260–6269} }