Reflectance properties of polymer-stabilised cholesteric liquid crystals cells with cholesteryl compounds of different functionality

In this paper, we describe the synthesis of cholesteryl compounds of different functionality. A series of polymer-stabilised cholesteric liquid crystal (PSCLC) cells are prepared by photo-polymerisation of a cholesteric liquid crystal (Ch-LC) mixture containing a non-reactive liquid crystal, a nematic diacrylate and the above cholesteryl compounds. The effect of cholesteryl compound functionality on the morphology and the reflectance properties of PSCLC cells is evaluated, as are parameters such as the polymerisation temperature. The results indicate that the higher functional cholesteryl compound is more effective for broadening the reflection band of the Ch-LC composites, which is speculated to be a result of the pitch differences in the local network environment. Scanning electron microscopy is used to examine the morphologies of the polymer network of the PSCLC cells. We have found that the morphologies of the polymer network are determined by the functionality of the cholesteryl compounds as well as polymerisation temperature, which further influence the reflectance properties of the composites.