Role of the photopolymerisation conditions in the broadening of the temperature range of the ‘blue phases’

Abstract

ABSTRACTThe influence of the photopolymerisation conditions during the formation of the blue phases (BPs) of the polymer-stabilised liquid crystal is reported. The reactive mesogen monomers (RMM) with various concentrations were added to the highly chiral thermotropic liquid crystal, which initially possesses a narrow temperature range of the existence of the BPs. The formation of the blue phases of the polymer-stabilised cholesteric liquid crystals (BP PSCLCs), containing cross-linking monomers without any photoinitiators, during their photopolymerisation in various phases (isotropic, BPs and cholesteric phase (Ch)), was independently studied in a relatively recent manuscript, published by H-Y Chen, et. al. Liq. Cryst., 2016. doi:10.1080/02678292.2016.1173244. In the present studies, the concentration dependencies of the RMM and the influence of the exposure time during the photopolymerisation process on the broadening of the temperature range and spectral features of the BPs were examined. Under certain experimental conditions, a maximal broadening of the temperature range of the existence of the BPs after the photopolymerisation process of cross-linking monomers carried out in the isotropic phase (Iso) not in the BP or the Ch was found.