Preparation of sulfur hydrophobized plasmonic photocatalyst towards durable superhydrophobic coating material

Abstract

The widely used photocatalytic self-cleaning coating materials are often made of polymers and polymer based composites, where the photocatalyst immobilization occurs with macromolecules. However, these organic polymers are often unstable under exposure to UV irradiation and easily degraded by reactive radicals produced in the photocatalytic reaction. In order to solve this problem, in this paper, we present the facile preparation of a multifunctional coating with dual superhydrophobic and photocatalytic properties, where the fixation and the hydrophobization of the plasmonic Ag-TiO2 photocatalyst particles with visible light activity was performed with non-water soluble sulfur, which is a cheap and easily available material. The resulted novel nanocomposite with rough and nano-tructured surface roughness (1.25–2.45 nm determined by small-angle X-ray scattering) has sufficient low surface energy (3.3 mJ/m2) for superhydrophobic (θ = 151.1°) properties. Moreover, in contrast of the organic and expensive fluoropolymer based composites, this non-wetting nature was durable, because the measured θ was higher than 150° during the long- term LED (λmax = 405 nm) light irradiation.