11 research outputs found

    Liquid Crystal Elastomer Waveguide Actuators

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    While most photomechanical materials developed to date have relied on free‐space illumination to drive actuation, this strategy fails when direct line‐of‐site access is precluded. In this study, waveguided light is harnessed by liquid crystal elastomer (LCE) nanocomposites to drive actuation. Using photo‐chemical reduction of gold salts to plasmonic nanoparticles, prescription of photoresponsive regions within fibers of mono‐domain LCEs is demonstrated with control over both the location along the fiber axis, as well as in the azimuthal direction. Due to localized photothermal heating provided by plasmonic absorption of waveguided light and resulting inhomogeneous thermally induced deformation of the LCE, reversible bending along multiple axes is demonstrated

    Reconfiguring Gaussian Curvature of Hydrogel Sheets with Photoswitchable Host–Guest Interactions

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    Photoinduced shape morphing has implications in fields ranging from soft robotics to biomedical devices. Despite considerable effort in this area, it remains a challenge to design materials that can be both rapidly deployed and reconfigured into multiple different three-dimensional forms, particularly in aqueous environments. In this work, we present a simple method to program and rewrite spatial variations in swelling and, therefore, Gaussian curvature in thin sheets of hydrogels using photoswitchable supramolecular complexation of azobenzene pendent groups with dissolved α-cyclodextrin. We show that the extent of swelling can be programmed via the proportion of azobenzene isomers, with a 60% decrease in areal swelling from the all trans to the predominantly cis state near room temperature. The use of thin gel sheets provides fast response times in the range of a few tens of seconds, while the shape change is persistent in the absence of light thanks to the slow rate of thermal cis–trans isomerization. Finally, we demonstrate that a single gel sheet can be programmed with a first swelling pattern via spatially defined illumination with ultraviolet light, then erased with white light, and finally redeployed with a different swelling pattern

    Multiaddressable Photochromic Architectures: From Molecules to Materials

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    Multiaddressable architectures comprising light‐responsive photochromic molecules and different stimuli‐responsive components are appealing platforms for intelligent materials because of not only the potential diversity of components and corresponding properties, but also the functions resulting from their synergistic interactions. A variety of multiaddressable photochromic architectures are being designed to meet the demands of applications in different areas ranging from molecular machines to smart materials. This review highlights exciting recent advances in the field of multiaddressable systems that employ photoswitching molecules, specifically with regard to photo‐/chemical‐addressable, photo‐/pH‐addressable, photo‐/thermal‐addressable, photo‐/redox‐addressable, and multi‐photoaddressable architectures. Design concepts, crosstalk between different components, and photoswitch integration in these multiaddressable systems are discussed
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