Photoregulation of the Low-Molecular-Weight Liquid-Crystals by the Photo-Aligned Liquid-Crystalline Polymer

Abstract

We investigated the alignment behavior of low-molecular-weight (LMW) liquid crystal (LC) on photoreactive side-chain liquid-crystalline polymer (SLCP) films induced by linearly polarized (LP) UV light. The effect of the LP-photoreaction conditions and the spacer length between the biphenyl and cinnamoyl groups were examined. The alignment direction of LMW-LC was parallel to the electric vector of the incident LP-UV light in the beginning of the photoreaction and changed to perpendicular when the most of the cirmamoyl group had reacted. These are the consequence of the difference of the interaction between LMW-LC and the biphenyl group or the photoreacted cinnamoyl group.