Role of liquid crystallinity of the photo-crosslinkable polymer film in the photo-alignment of mesoporous silica

A new photo-aligning technique for mesochannels of a silica thin film transferred from a liquid crystalline photo-crosslinkable polymer (poly[6-(4-(4′-methoxycinnamoyloxy)biphenyloxy)hexylmethacrylate] (PMBCi)) film has been developed in our group. Herein, we also adopt a non-liquid crystalline photo-crosslinkable polymer, poly(vinyl cinnamate) (PVCi), to evaluate the role of liquid crystallinity for inducing the alignment of mesochannels of the silica films. Optical anisotropy of the thin films of the two photo-crosslinkable polymers (PVCi and PMBCi) was induced by irradiation with linearly polarized UV (LPUV) light. The photo-induced anisotropy of both films were sufficient for alignment of nematic liquid crystal molecules, however, mesoporous silica films were aligned only on the liquid crystalline PMBCi film as revealed by in-plane X-ray diffraction (XRD) measurements and optical microscopy.