Optimization of Sol-Gel Film Properties

Abstract

ABSTRACTThe preparation and characterization of organic-modified and organic/ iorganic-modified silica sol-gel spin-coated thin films is presented as a function of thermal processing. The ability to alter the film's final refractive index, thermal expansion coefficient and the polar contribution to the film's surface energetic term is reported. The stability of the coating solution at elevated temperatures was studied by analyzing changes in molecular weight, viscosity and particle size during the sol-to-gel transition. Control of the sol-gel thin film properties allows the design of a film/substrate interface where both thermal mismatches and surface energetic differences are minimized. Decreased stresses should be induced during processing, resulting in increased adhesion between the coating and the substrate.