Macromolecules, Vol.39, No.2, 690-696, 2006
Alignment of liquid crystal on poly [methyl(phenyl)silylene] films treated with polarized UV light
The alignment of liquid crystal (LC) on poly [methyl (phenyl)silylene] (PMPSi) films treated with linearly polarized light is reported. Simultaneous measurements of the photoinduction of dichroism in the PMPSi films and of the azimuthal anchoring energy of LC on these films revealed the absence of a correlation in the kinetics of both processes. The azimuthal anchoring energy of LC reaches its maximum at the beginning of the irradiation where the dichroism is still neglectful. On further irradiation the dichroism increases, but the azimuthal anchoring energy of the LC drops to zero. To explain this behavior, detailed investigations of photoinduced processes in PMPSi films caused by irradiation with UV light were performed. It was found that anisotropic distribution of ion pairs in the direction of the polarization of the exciting light plays an essential role in the alignment of LC.