Bandwidth-controllable reflective cholesteric gels from photo- and thermally-induced processes

A bandwidth-controllable reflective gel has been investigated from photo- and thermally-induced processes. Due to the pitch of cholesteric liquid crystal (CLC) composite increasing as the temperature rises, the CLC with short pitch is frozen by UV-curing the polymer network at low temperature and the CLC with long pitch is fixed by heat curing the polymer network at high temperature. A non-uniform pitch distribution of CLCs forms in the gel when temperature becomes low. It is demonstrated that the memory effect of the polymer network is an important mechanism for the resulting gel.