Novel Liquid Crystal Photoalignment System Based on New soluble Polyimide

摘要

Novel liquid crystals (LCs) photoalignment system, which exhibits outstanding photosensitivily and excellent thermal stability, has been developed based on new soluble polyimide. Homogeneous alignment of liquid crystals (LCs) was induced by soluble polyimide (CMPI) having chloromethyl side groups upon irradiation, of linearly polarized UV light (LPUVL) with short irradiation time. The pholoaligned film was thermally stable without destroying LC alignment when LC cell was stored- at 85 deg C for 14 days. The pretill angle of LC decreased, with irradiation lime, which is contributed by the increased polar surface energy of CMPI film after irradiation of LPUVL. FT-IR spectra confirmed that the pholosensilivily of polyimide was improved greatly by introducing chloromethyl group and the alignment of LC was contribute by the photo-decomposition of polyimide main chain- upon irradiation.