Surface Property and Stability of Transparent Superhydrophobic Coating Based on SiO2-Polyelectrolyte Multilayer

Abstract

Artificial superhydrophobic films were deposited onto a glass slide by performing layer-by-layer deposition of 3.5 bilayers of poly(allylamine hydrochloride)/ poly(acrylic acid) polyelectrolyte, followed by a layer of SiO₂ nanoparticles of various amounts to enhance the surface roughness and a fluorosilane to reduce the surface free energy. Higher SiO₂ content incorporated into the films resulted in rougher surface and higher water contact angle. The total surface free energy determined by using the Owens-Wendt equation dramatically decreased from 31.46 mJ·m^-2 for the film having the relatively flat surface to only 1.16 mJ·m^-2 for the film having the highest surface roughness of 60.2 ± 1.1 nm. All the films were optically transparent and had excellent adhesion based on the peel test. Indoor and accelerated weathering tests revealed good weathering stability.

DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12952