Fast switchable field-induced optical birefringence in highly transparent polymerliquid crystal composite

A liquid crystal device with optically isotropic liquid crystal (OILC) phase induced from polymerization-induced phase separation exhibit a fast response time and a proper dark state. Its electro-optic performances are highly influenced by a kind of materials and processing conditions. Here, the effect of materials and phase-separation on the electro-optic performance of OILC device has been investigated by utilizing the acrylate and the thiol-ene monomer mixtures. The optically isotropic phase was analyzed with scattering theory, and it was revealed that a novel polymer network structure of acrylate mixture is free of scattering and yields a higher on-state transmittance, enhanced by ~50%. By tuning the monomer ratio and UV intensity, an excellent transparent film was obtained and, in addition, the response time was improved by ~40%. The excellent black state and its flexibility can be applied to flexible liquid crystal photonic and display devices.