Improvement of electro-optical properties on polymer-stabilised optically isotropic liquid crystals

A relation between preparation conditions of polymer-stabilised optically isotropic liquid crystals and their electro-optical properties was investigated based on a cyclic voltammetric (CV) method. The polymer-stabilised optically isotropic liquid crystals were prepared by an in-situ photo-polymerisation of a precursor consisting of a chiral liquid crystalline mixture with monomers in an isotropic phase with a metal halide lamp. The CV response of the cell filled with the sample showed an asymmetric profile and a symmetric profile between the positive and negative applied voltages when the cell was irradiated with the metal halide lamp without filter and with a cut-off wavelength filter (> 390 nm), respectively. The CV response profile depends on a distributed state of the polymer generated in the cell. The residual birefringence of the polymer-stabilised optically isotropic phase was suppressed when the CV profile showed a symmetric profile.