Preparation of Optical Scattering Thin Film Utilizing Phase Separation in Sol-Gel Process

Abstract

By inducing a phase separation parallel to the sol-gel transition of an alkoxy-derived silicate system, silica-based concavo-convex thin film having optical scattering function was made on a glass substrate. A homogeneous coating solution including organically-modified silicon alkoxide, solvent with high solubility parameter and alcoholic solvent was prepared and was coated on a glass substrate. Concavo-convex thin film was fixed on the substrate by controlling phase separation and sol-gel transition during a drying process. Semi-sphere-like convexes from 5 to 50μm in diameter and from 0.2 to 1μm in height were irregularly arranged at the surface of the film. In this presentation, composition of the coating solution, the formation process and optical scattering properties of the concavo-convex film are presented.