Synthesis and Characterization of Durable Antifog Silane–Pyrrolidone Thin Coatings onto Polymeric Films

Abstract

The fogging of transparent surfaces—condensation of water vapor in the air to a small liquid surface at specific environmental conditions—scatters incident light, creating a blurry vision. Fogging presents a significant challenge in various industries, adversely affecting numerous applications including plastic packaging, agricultural films, and various optical devices. Superhydrophobic or superhydrophilic coatings are the main strategies used to induce antifogging to minimize light scattering. Here, an innovative approach is introduced to mitigate fogging by modifying the surface properties of polymeric films, focusing on corona-treated polyethylene as a model. Coatings were prepared in two successive steps: the addition of radical co-polymerization of methacryloxypropyltriethoxysilane and N-vinylpyrrolidone followed by the step-growth Stöber polymerization of the formed silane monomer. The polymeric dispersion was spread on oxidized films via a Mayer rod and dried. Scanning and force microscopy, FIB, XPS, and UV-vis spectroscopy revealed a thin coating composed of cross-linked siloxane (Si-O-Si) covalently bonded to surface hydroxyls exposing pyrrolidone groups. Contact angle measurements, hot-fog examination, and durability tests indicated a durable antifogging activity.