Non‐crystalline, transparent methylsilsesquioxane–titania hybrid films for application in micropatterning were prepared from methyltriethoxysilane and titanium tetrabutoxide by the sol–gel method. The hybrid films were heat‐treated at 100 °C for 1 h and then irradiated with UV light using an ultrahigh‐pressure mercury lamp. The refractive index of the film increased as the amount of incorporated TiO2 increased. No changes in hardness were observed for the films lacking TiO2 during UV irradiation, whereas adding a small amount of TiO2 caused the hardness to increase significantly following UV irradiation. These changes in the physical properties of the films with UV irradiation were caused by the cleavage of Si–C bonds in the films induced by the photocatalytic effect of TiO2. On the basis of the changes in surface profiles, and optical, chemical, and mechanical properties induced by UV irradiation, it is concluded that the methylsilsesquioxane–titania films are promising for micropatterning by photolithography.
Sol gel derived phenylsilsesquioxane (PhSiO 3/2 ) methylsilsesquioxane (MeSiO 3/2 ) films were prepared on soda-lime-silicate (SLS) glass substrates by dropping and spreading method. The mechanical properties of the pure MeSiO 3/2 and 20PhSiO 3/2 · 80MeSiO 3/2 (in mol %) films were measured as a function of heat treatment times and temperatures using a nanoindentation test with a Berkovich indenter. The relative residual depth (² r ) of films decreased and the film hardness (H M ) significantly increased with increasing heat treatment times and temperatures. The mechanical properties of the films well reflect the changes in the chemical structures and the evolution of siloxane networks with the heat treatment.
The influence of ultraviolet (UV) irradiation on vinylsilsesquioxane (ViSiO 3/2 ) films was investigated using a nanoindentation technique, and the structural changes were analyzed. Solid-state 13 C cross-polarization magic-angle-spinning nuclear magnetic resonance and infrared spectra of the films confirmed the polymerization of C=C bonds and formation of a CC bridge structure upon UV irradiation. Since the vinyl group is a photosensitive organic component with a short organic chain, it is expected to show a large improvement in mechanical properties as a result of the formation of an organic network under the influence of UV irradiation. It is shown that varying the intensity of the UV irradiation leads to changes in the hardness and elasticity. The irradiation energy was found to determine the mechanical properties of the ViSiO 3/2 films, regardless of the effects of different UV intensities on the hybrid films.
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