Effects on thermo-optical properties of the composition of a polymer-stabilised liquid crystal with a smectic A-chiral nematic phase transition.

A photopolymerisable monomer/liquid crystal (LC)/chiral dopant/photoinitiator mixture with a smectic A (SmA*)-chiral nematic (N*) phase transition was prepared. After the SmA* phase was homeotropically oriented and then irradiated by ultraviolet light, a homeotropically oriented polymer network was formed in the SmA* phase and then a homeotropically oriented polymer network-stabilised liquid crystal (PSLC) film with a SmA*-N* phase transition was prepared. In the temperature range of the SmA* phase, the LC molecules were homeotropically oriented and the film exhibited a transparent state. However, in the temperature range of the N* phase, the film exhibited a strong light-scattering state owing to the fact that the LC molecules adopted a focal conic alignment affected by the homeotropically oriented polymer network. The strong light-scattering state of the N* phase could be changed into a transparent one when an electric field was applied. The focus of this study was on the effects of composition of the PSLC film on its thermo-optical and electro-optical properties. [ABSTRACT FROM AUTHOR]