STUDIES ON PREPARATION AND PROPERTIES OF ORGANIC/INORGANIC HYBRID TRANSPARENT FILMS WITH HIGH REFRACTIVE INDEX

Abstract

High refractive index organic/inorganic hybrid films have attracted considerable attention in both fundamental and applied research as hard coatings for organic resins.Among these hybrid materials,TiO_2 is a typical candidate for hybrid components due to its high refractive index and hardness.In this article,a series of titania containing organic/inorganic hybrid films with high refractive index and performance were prepared by co-hydrolysis of silane coupling agent (3-glycidyloxypropyl) trimethoxysilane (KH-560) and titanium butoxide [Ti(OBu)_4] through sol-gel method without using any stabilizer.Our method improved the optical and mechanical properties of the resultant hybrid coatings.The microstructure,optical,mechanical and thermal properties of the hybrid films were characterized by using different methods. FTIR indicates that the different components have been successfully combined to hybrids by covalent bonds.TGA indicates these hybrid films have good thermal durability.AFM and TEM indicate that the films have smooth surface, and the titania nano-phases (3 nm) were well dispersed in all the films without aggregations even in the film with high titania content.UV-Vis transmission spectra indicate that the hybrid films have high transparency of above 90% in the range of visible light,which is in accordance with AFM and TEM results.In addition,the refractive index of the hybrid films could be adjusted linearly from 1.5 to 1.7 by altering the titania content.The pencil hardness of the films is 4～5 H both before and after aging, and all the films have good adhesion performance to substrate materials.The hybrid films have potential applications in filters,optical waveguide,lenses and antireflection films.