Molecular engineering of the polymer stabilizing network to enhance the electro-optic response of cholesteric liquid crystals

Abstract

The selective reflection inherent to the cholesteric liquid crystal (CLC) phase (in the planar orientation) can be tuned or broadened by the incorporation of polymer stabilizing networks (PSCLC). Prior reports detail that the mechanism is ion-mediated deformation of the polymer stabilizing network, which retains structural chirality. The structural chirality of the polymer stabilizing effectively overpowers the chirality of the CLC mixture. Here, we incorporate monomers containing groups known to trap cationic metal halide ions, into the polymer stabilizing network. Specifically, we incorporate monofunctional control monomers as well as monofunctional acrylate monomers 4-acryloxyhexylterpyridine (TPy-Ac), 4-((6-(acryloyloxy)hexyl)oxy)benzoic-15-crown-5 (OBA-15C5), and 4-((6-(acryloyloxy)hexyl)oxy)benzoic-18-crown-6 (OBA-18C6). The electro-optic response is enhanced only by the inclusion of OBA-15C5 which previously has been shown to selectively trap and interact with sodium (Na⁺) ions.