Preparation and Characterization of Silica/Polymer Antifogging Coatings

Abstract

This research work concerns the preparation of a bi-layer antifogging (AF) coating on a polycarbonate plastic substrate. The bottom layer, serving as a mechanical support, is an organic-inorganic composite that is formed by embedding colloidal silica in a crosslinked network of γ-glycidoxypropyltrimethoxysiline. Atop this layer, a coating formulation incorporating glycidyl methacrylate and poly(ethylene oxide)-based hydrophilic species was applied and then UV-cured to yield a film exhibiting the AF effect. Solid-state 29Si-NMR and FTIR were employed to investigate the evolution of chemical bonds during the sol-gel and the UV-curing processes. Contact angles of water on the coatings were measured to examine the hydrophilicity of the coatings. Furthermore, industrial tests such as pencil hardness, tape adhesion, and steam tests were carried out to evaluate the performance of the coatings.