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Cholesteric liquid crystals (CLCs) exhibit Bragg reflection due to their spontaneous self-assembly into a one-dimensional photonic structure. Retaining this cholesteric order in a polymer network requires functionalizing liquid crystals with reactive end groups. However, conventional chemistries for synthesizing cholesteric liquid crystalline polymers often result in poor surface alignment and reduced optical quality. In this work, we investigate a thiol−ene step-growth polymerization approach to fabricate cholesteric liquid crystalline elastomers (CLCEs) with tunable mechanical properties and improved optical quality. By varying the cross-link density, we systematically study the effects on haze, cross-linking degree, and mechanical response. Compared to existing cholesteric liquid crystalline polymers, the thiol−ene-based CLCEs exhibit enhanced surface alignment, reduced haze, and greater mechanical tunability. These materials are further benchmarked against CLCEs synthesized via thiol−acrylate chain transfer polymerization, highlighting the advantages of the thiol−ene reaction for achieving precisely controlled properties in cholesteric polymer networks.
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Photo‐Controlled Dynamics of Cholesteric Polymer Coatings via Hydrazone Crosslinking
Abstract Developing responsive coatings and materials requires discovering a breadth of mechanisms by which external stimuli can be converted into useful signals. Here, we demonstrate an approach driven by supramolecular mechanochemistry, where mechanical input—molecular shape change—is translated into structural color variation. By embedding bistable, negatively photochromic hydrazone photoswitches into cholesteric polymer networks, we achieve a reversible, stable color shift through molecular‐scale pulling and pushing of the photonic scaffold. Unlike azobenzene‐based systems, which typically disrupt liquid crystal order, this approach modifies the pitch of a cross‐linked cholesteric helix without disrupting the organisation of the material. The long‐lived stability of both hydrazone isomers ensures durable optical switching. This effect provides a new strategy for designing mechanoresponsive photonic coatings and tunable optical materials.
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- Award ID(s):
- 2104464
- PAR ID:
- 10600216
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 31
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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