posted on 2024-03-18, 06:03authored byHayden
E. Fowler, Harrison M. Pearl, Jonathan D. Hoang, Timothy J. White
Liquid
crystal elastomers (LCEs) assimilate the anisotropy of liquid
crystalline phases with the rubber elasticity of polymer networks.
Numerous recent reports detail the preparation of LCEs by sequential
chain extension reactions of diacrylate liquid crystalline monomers
followed by the photopolymerization of liquid crystalline oligomers.
While these reactions are widely utilized, sample fabrication can
take hours or even days. Other reports detail the preparation of LCEs
via direct thiol–acrylate photopolymerization via free radical
chain transfer reactions. While this is a rapid and straightforward
approach to preparing LCEs, the topology of the polymer network composition
is heterogeneous, with wide variance in molecular weight between cross-links
and extensive prevalence of pendant groups. Here, we detail the preparation
of LCEs via thiol–ene photopolymerization. The compositions
introduced here are amenable to surface-enforced alignment, which
enables the high-fidelity inscription of complex director profiles.
Compared to prior thiol-based LCE compositions, direct preparation
of LCE by thiol–ene photopolymerization is rapid, forms largely
homogeneous polymer networks, and has wide tunability in cross-link
density.