@article{yadav_rizvi_kuttich_mishra_chapman_lynch_kraus_oldenburg_tracy_2021, title={Plasmon-Coupled Gold Nanoparticles in Stretched Shape-Memory Polymers for Mechanical/Thermal Sensing}, volume={4}, url={https://doi.org/10.1021/acsanm.1c00309}, DOI={10.1021/acsanm.1c00309}, abstractNote={The organization of plasmonic nanoparticles (NPs) determines the strength and polarization dependence of coupling of their surface plasmons. In this study, plasmon coupling of spherical Au NPs with an average diameter of 15 nm was investigated in shape-memory polymer films before and after mechanical stretching and then after thermally driving shape recovery. Clusters of Au NPs form when preparing the films that exhibit strong plasmon coupling. During stretching, a significant polarization-dependent response develops, where the optical extinction maximum corresponding to the surface plasmon resonance is redshifted by 19 nm and blueshifted by 7 nm for polarization parallel and perpendicular to the stretching direction, respectively. This result can be explained by non-uniform stretching on the nanoscale, where plasmon coupling increases parallel to the shear direction as Au NPs are pulled into each other during stretching. The polarization dependence vanishes after shape recovery, and structural characterization confirms the return of isotropy consistent with complete nanoscale recovery of the initial arrangement of Au NPs. Simulations of the polarized optical responses of Au NP dimers at different interparticle spacings establish a plasmon ruler for estimating the average interparticle spacings within the experimental samples. An investigation of the temperature-dependent recovery behavior demonstrates an application of these materials as optical thermal history sensors.}, number={4}, journal={ACS Applied Nano Materials}, publisher={American Chemical Society (ACS)}, author={Yadav, Prachi R. and Rizvi, Mehedi H. and Kuttich, Björn and Mishra, Sumeet R. and Chapman, Brian S. and Lynch, Brian B. and Kraus, Tobias and Oldenburg, Amy L. and Tracy, Joseph B.}, year={2021}, month={Mar}, pages={3911–3921} }
 @article{chapman_mishra_tracy_2019, title={Direct electrospinning of titania nanofibers with ethanol}, volume={48}, url={https://doi.org/10.1039/C9DT01872G}, DOI={10.1039/c9dt01872g}, abstractNote={TiO<sub>2</sub> nanofibers with average diameters of ∼70 nm were prepared by direct electrospinning.}, number={34}, journal={Dalton Transactions}, publisher={Royal Society of Chemistry (RSC)}, author={Chapman, Brian S. and Mishra, Sumeet R. and Tracy, Joseph B.}, year={2019}, month={Jan}, pages={12822–12827} }
 @article{liu_gillen_mishra_evans_tracy_2019, title={Photothermally and magnetically controlled reconfiguration of polymer composites for soft robotics}, volume={5}, url={https://doi.org/10.1126/sciadv.aaw2897}, DOI={10.1126/sciadv.aaw2897}, abstractNote={New materials are advancing the field of soft robotics. Composite films of magnetic iron microparticles dispersed in a shape memory polymer matrix are demonstrated for reconfigurable, remotely actuated soft robots. The composite films simultaneously respond to magnetic fields and light. Temporary shapes obtained through combined magnetic actuation and photothermal heating can be locked by switching off the light and magnetic field. Subsequent illumination in the absence of the magnetic field drives recovery of the permanent shape. In cantilevers and flowers, multiple cycles of locking and unlocking are demonstrated. Scrolls show that the permanent shape of the film can be programmed, and they can be frozen in intermediate configurations. Bistable snappers can be magnetically and optically actuated, as well as biased, by controlling the permanent shape. Grabbers can pick up and release objects repeatedly. Simulations of combined photothermal heating and magnetic actuation are useful for guiding the design of new devices.}, number={8}, journal={Science Advances}, author={Liu, Jessica A.-C. and Gillen, Jonathan H. and Mishra, Sumeet R. and Evans, Emily E. and Tracy, Joseph B.}, year={2019}, month={Aug} }
 @article{schmauch_mishra_evans_velev_tracy_2017, title={Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robots}, volume={9}, url={https://doi.org/10.1021/acsami.7b01209}, DOI={10.1021/acsami.7b01209}, abstractNote={Magnetic field-directed self-assembly of magnetic particles in chains is useful for developing directionally responsive materials for applications in soft robotics. Using materials with greater complexity allows advanced functions, while still using simple device architectures. Elastomer films containing chained magnetic microparticles were prepared through solvent casting and formed into magnetically actuated lifters, accordions, valves, and pumps. Chaining both enhances actuation and imparts a directional response. Cantilevers used as lifters were able to lift up to 50 times the mass of the polymer film. We introduce the "specific torque", the torque per field per mass of magnetic particles, as a figure of merit for assessing and comparing the performance of lifters and related devices. Devices in this work generated specific torques of 68 Nm/kgT, which is significantly higher than in previously reported actuators. Applying magnetic fields to folded accordion structures caused extension and compression, depending on the accordion's orientation. In peristaltic pumps comprised of composite tubes containing embedded chains, magnetic fields caused a section of the tube to pinch closed where the field was applied. These results will facilitate both the further development of soft robots based on chained magnetic particles and efforts to engineer materials with higher specific torque.}, number={13}, journal={ACS Applied Materials & Interfaces}, author={Schmauch, Marissa M. and Mishra, Sumeet R. and Evans, Emily E. and Velev, Orlin D. and Tracy, Joseph B.}, year={2017}, month={Mar}, pages={11895–11901} }
 @article{pacardo_neupane_rikard_lu_mo_mishra_tracy_wang_ligler_gu_2015, title={A dual wavelength-activatable gold nanorod complex for synergistic cancer treatment}, volume={7}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000357805700034&KeyUID=WOS:000357805700034}, DOI={10.1039/c5nr01568e}, abstractNote={A multifunctional gold nanorod complex was formulated for synergistic anticancer treatment upon ultraviolet (UV) and infrared (IR) light dual irradiations.}, number={28}, journal={Nanoscale}, author={Pacardo, Dennis B. and Neupane, Bhanu and Rikard, S. Michaela and Lu, Yue and Mo, Ran and Mishra, Sumeet R. and Tracy, Joseph B. and Wang, Gufeng and Ligler, Frances S. and Gu, Zhen}, year={2015}, month={Jan}, pages={12096–12103} }
 @article{mishra_dickey_velev_tracy_2015, title={Selective and directional actuation of elastomer films using chained magnetic nanoparticles}, volume={8}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000368040200008&KeyUID=WOS:000368040200008}, DOI={10.1039/c5nr07410j}, abstractNote={One-dimensional arrangement of magnetic nanoparticles in chains imparts anisotropy to their magnetic response, which is used for mechanical 3D actuation.}, number={3}, journal={Nanoscale}, publisher={Royal Society of Chemistry (RSC)}, author={Mishra, Sumeet R. and Dickey, Michael D. and Velev, Orlin D. and Tracy, Joseph B.}, year={2015}, month={Nov}, pages={1309–1313} }
 @article{kozek_kozek_wu_mishra_tracy_2013, title={Large-Scale Synthesis of Gold Nanorods through Continuous Secondary Growth}, volume={25}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000327752500010&KeyUID=WOS:000327752500010}, DOI={10.1021/cm402277y}, abstractNote={Gold nanorods (GNRs) exhibit a tunable longitudinal surface plasmon resonance (LSPR) that depends on the GNR aspect ratio (AR). Independently controlling the AR and size of GNRs remains challenging but is important because the scattering intensity strongly depends on the GNR size. Here, we report a secondary (seeded) growth procedure, wherein continuous addition of ascorbic acid (AA) to a stirring solution of GNRs, stabilized by cetyltrimethylammonium bromide (CTAB) and synthesized by a common GNR growth procedure, deposits the remaining (~70%) of the Au precursor onto the GNRs. The growth phase of GNR synthesis is often performed without stirring, since stirring has been believed to reduce the yield of rod-shaped nanoparticles, but we report that stirring coupled with continuous addition of AA during secondary growth allows improved control over the AR and size of GNRs. After a common primary GNR growth procedure, the LSPR of GNRs is ~820 nm, which can be tuned between ~700-880 nm during secondary growth by adjusting the rate of AA addition or adding benzyldimethylhexadecylammonium chloride hydrate (BDAC). This approach for secondary growth can also be used with primary GNRs of different ARs to achieve different LSPRs and can likely be extended to nanoparticles of different shapes and other metals.}, number={22}, journal={Chemistry of Materials}, author={Kozek, Krystian A. and Kozek, Klaudia M. and Wu, Wei-Chen and Mishra, Sumeet R. and Tracy, Joseph B.}, year={2013}, month={Oct}, pages={4537–4544} }