Surface-Aligned Cholesteric Liquid Crystalline Elastomers with Tunable Mechanical Properties via Thiol–Ene Chemistry

Abstract

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.