Sol-Gel Preparation of Titania/Organic Silicone Hybrid Thin Films

Incorporation of metal alkoxides into polymers through Sol-Gel process is of significant interest for tuning the refractive index of optical materials. The organic-Inorganic hybrid material with tunable refractive index (RI) and high transparency was studied. Tetrabutoxytitanate, (TBOT) and alkoxysilanes including diphenyldimethoxysilane (DPS) and gamma-Glycidoxypropyl trimethoxysilane (GPTS) were employed as sources of the titania sol and the silica sol respectively. Subsequently, crack-free films were fabricated by spill coating. The hybrid films with different Ti contents were characterized by various techniques Including IR, UV-Vis, TG/DSC, TEM and auto-laser ellipsometer. The results indicated that the hybrid films displayed homogeneous morphology and titania was crosslinked with alkoxysilanes. The RI of films increased from 1.54 to 1.64 at 633nm with Ti molar fraction varing from 10% to 70%. And the transmittances of the hybrid films in the visible range were higher than 90%.