Hydrogen-bonded photoreactive polymer liquid crystal containing pyridyl-terminated n-benzylideneaniline

Abstract

Three kinds of polymeric composites consisting of a monomeric pyridine-terminated photoreactive compound and polymethacrylate with photo-inactive benzoic acid side chains were prepared and their photoinduced reorientation behavior was investigated using linearly polarized (LP) UV light and thermally induced self-organization. Due to the different structures of the photoreactive dopants, the reorientation direction and performance were different among the samples. The dopant containing methoxybiphenyl and pyridine connected by an imine bond exhibited no mesomorphism and underwent a slight axis-selective photoreaction in the composite, while the dopant with phenylpyridine and methoxybenzene showed a nematic phase and exhibited axis-selective photoreaction but no thermo-induced amplification of anisotropy in the composite. On the other hand, the dopant consisting of pyridine and methoxybenzene showed a nematic phase with a low glass transition temperature by combination with the host polymer. The composite exhibited thermo-induced molecular reorientation behavior by LPUV exposure below room temperature and subsequent annealing at 120 οC.