Modifying a waterborne polyacrylate coating with a silica sol for enhancing anti-fogging performance

Abstract

Hydrophilic anti-fogging coatings are necessary for transparent substrates, which can enable water to spread uniformly to avoid fogging. However, the transparency and the adherence to the underlying substrate of the anti-fogging coating reported are not yet optimal. In this article, we reported on a hydrophilic anti-fogging coating that could maintain good transparency and adherence. The coating was prepared by a waterborne polyacrylate modified silica sol precursor. Firstly, a silica sol precursor was synthetized by hydrolyzing tetraethoxysilane in an aqueous medium and then was introduced into the polyacrylate emulsion to in situ generate the crosslinking structure. The presence of the silica sol improved the hydrophilicity of the waterborne polyacrylate emulsion coating with a water contact angle as low as 11° (static water contact angle). And water droplets could spread out rapidly, which afforded the polyacrylate/silica composite coating with good anti-fogging ability (without forming water droplets) in a humidifier test. Furthermore, transmittance and adherence of the substrate were well maintained after the deposition of the composite coating.