Liquid Crystal Photonics : Optical Control of Nematic Liquid Crystals with Photosensitive Polyimides Alignment Layers Having Different Photoactive Moieties

Abstract

In this study, we used eight types of polyimides (PIs) which were prepared by thermal imidization of poly(amide acid)s as the precursor and evaluated the optical switching behavior of nematic liquid crystals (NLCs; 5CB and ZLI-4751) with the photosensitive PIs as alignment layer. The photosensitive PIs as alignment layer induced the optical switching of NLCs. The optical switching behavior of NLCs was dependent on the structure of PIs. We also found that the optical switching behavior was affected by degree of imidization, light intensity, temperature, and polarity of NLCs. The surface component of the PI shifted from the dispersion component to the polar component, which resulted in decrease of the surface tension between NUC and the PI film due to rubbing. The surface property of PI film was closely related to the optical switching behavior of NLCs.