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

Abstract

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.

Keywords:

• cyclic voltammetric measurement
• optically isotropic liquid crystal
• residual transmittance

Acknowledgements

This work was partly supported by the Japan Science and Technology Agency. We thank Mr Masaru Inoue for the fruitful discussions and Ms Rio Miyazaki for the technical support in the electro-optical measurements. The author would also like to thank Dr Miyazawa for his kind support.