The facile synthesis of well-aligned, main-chain liquid crystalline elastomers (LCEs) that retain the cholesteric phase (CLCEs) is reported. The selective reflection inherent to this phase is thermally tuned more than 200 nm in these solid films, across the visible spectrum. The optical response is directly correlated to thermomechanical expansion of the CLCE film thickness. The bandwidth of the selective reflection of the CLCEs is increased to more than 200 nm by the incorporation of photosensitive chiral dopants that introduce heterogeneity in the pitch distribution. The mirror-like reflection of this CLCE film is also thermochromic, shifting from the visible to infrared. Reminiscent of cephalopods, when combined with the mechanical deformation of voxelated nematic LCE, the thermochromic response of the CLCE produces solid-state elements with concurrent variation of specular and diffuse reflectance. These results demonstrate distinctive potential opportunities for liquid crystal elastomers to control light enabling new application in textiles, optics, and architecture.
Liquid crystalline elastomers (LCEs) are well known for their stimuli-responsive behavior. Of interest to the work presented here is the distinctive, nonlinear deformation of these materials to load. Here, we assess the cyclic deformation and elastic recovery of acrylate-based LCEs synthesized by chain-transfer reactions. Mechanical deformation of the LCEs (prepared with this synthetic approach) beyond a threshold strain value does not elastically recover, unless heat-treated. The thermomechanical actuation of these materials exhibits limited hysteresis over five cycles. Exploration of the deformation mechanics and elastic recovery extends the understanding of this material composition and informs its potential use in applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.