ABSTRACT

With birefringent mesogens in side chain or main chain, LC polymers (LCPs) integrate LC properties with high-performance polymer materials possessing a film-forming nature, high processability, easy-fabrication characteristics, high corrosion resistance, and low manufacturing costs. Introduction of photoresponsive mesogens into LCPs provides the designed materials with photocontrolled features, as shown in Fig. 5.1. Among them, photochemical phase transition and photocontrolled alignment are the most important ones. Therefore, the photoresponsive LCPs have been widely explored as promising photonic materials due to their controllable properties in response to light. For photoresponsive features, side-chain LCPs are usually superior to main-chain ones because the latter usually exhibits lack of molecular mobility by confining mesogens in macromolecular main chain. Scheme 5.1 shows synthesis of one typical nematic LCP with photoisomerizable azobenzenes in side chain as nematic mesogens.