Broaden reflection bandwidth of chiral nematic liquid crystals by chiral compound-loaded thermally responsive microcapsules

Abstract

Controllable broadband reflection of cholesteric liquid crystal (N*-LC) materials has sparked enormous interests due to its significance in areas such as infrared shielding glass films and LC displays. In this study, we report a novel method to broaden the bandwidth of the chiral nematic liquid crystal (N*-LC) by a thermally responsive microcapsule (TRMC) loaded with chiral compound. Diffusion of chiral compound loaded in the microcapsules triggered by heating resulted in non-uniform pitch distribution, which were locked by UV-radical polymerisation. The results showed that the reflection bandwidth could be broadened by adjusting mass of the microcapsules, heating time, UV intensity, concentration of UV-polymerisable free radical monomer and polymerisation temperature. The reflection bandwidth was broadened from 240 nm to 374 nm by optimising the above factors.