Photo sensitivity of titania-doped hybrid polymer prepared by an anhydrous sol-gel process

摘要

Methacrylate-modified hybrid polymer with varied TiO_2 concentrations was prepared by an anhydrous sol-gel process, and the effects of TiO_2 on the photosensitivity of the hybrid polymer in the forms of wet films (before the polymerisation of the unsaturated C = C bonds of methacrylate groups) and hard films (after the polymerisation of the unsaturated C=C bonds with a pre-UV cross-linking and thermo-curing process) were studied. TiO_2 doping was found useful for enhancing the photosensitive response to UV light irradiation in both wet and hard films. In wet films, TiO_2 has a similar effect as a photo-initiator on accelerating the polymerisation of the unsaturated C = C bonds of methacrylate groups, therefore TiO_2 doping favours UV-patterning with photolithographic process for planar optical waveguides fabrication. In the fully polymerised TiO_2-doped hard films, photosensitivity with a refractive index increase as large as 0.01 was firstly observed. The structural changes of the hybrid polymer upon UV irradiation were investigated by FT-IR and energy dispersive X-ray spectroscopic (EDXS) techniques, and the mechanisms for the photosensitivity in hard films were proposed.