Photoalignment properties of nematic LCs on polyamide-imide films exposed to polarized UV light

摘要

Photoalignment properties of Nematic liquid crystals (LCs) on polyamide-imide films exposed to polarized UV light were investigated. It was found that polyamideimides brought about the unidirectional LC alignment, however, the uniformity of LC alignment depended on the chemical structure of polyamide-imides. The excellent uniform LC alignment was achieved on some of polyamide-imides containing the cyclobutane ring in tetracarboxylic dianhydride component and the amide group in diamine component with irradiation of light at not only 254 nm but also 313 nm. It is considered that the decomposition of cyclobutane ring and the photoreaction of amide group occurred in these polyamide-imides.