2D02 ポリイミド主鎖にアゾ基を持つ光配向膜 : (I) 光安定性と熱安定性

抄録

We have investigated the thermal and optical stabilities of the photo-alignment layers for nematic liquid crystals (LCs). For the photo-alignment layers, three kinds of photo-isomerizable polymer systems were studied; a polyamic acid doped with azebenzene molecules, a side-chain-substituted polyamic acid with azobenzene units, and a main-chain-substituted polyamic acid with azobenzene units. Photo-induced anisotropy was assessed by polarized UV absorption spectra and optical birefringence. The nematic LC-aligning properties were investigated using the photo-alignment layers processed at various thermal and optical conditions. It was found that the main-chain polyimide system was shown to exhibit good unidirectional LC alignment and excellent thermal (300℃ for 1 hour) and optical stabilities. Moreover, we suggest the new procedure, in which the photo-illumination process should be done before the thermal imidization process, to achieve the stable photo-alignment layer.