Preparation and Property of Superhydrophobic and Photocatalytic Polydimethylsilane/Nano-TiO₂ Self-Cleaning Coating

Combining the photocatalytic activity with the superhydrophobicity of coating is an effective approach for the self-cleaning effect. In this paper, the porous aluminum surface was coated with trialkoxy-terminated polydimethylsiloxane/titanium dioxide (PDMS/TiO₂) coating (APT) by a solution immersion method. According to the analysis by Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy, a bond (Ti—O—Si) between PDMS and TiO₂ is formed. The results by scanning electron microscopy and energy dispersive spectroscopy show that the superhydrophobicity is due to the interconnected hierarchical sheet structure and the PDMS with a low surface energy. The surface of APT coating has a stable superhydrophobicity with a water contact angle (WCA) of 161.6° and a sliding angle of less than 10°. The stability of superhydrophobicity with WCAs greater than 150° remains after 24 h ultraviolet irradiation. The ATP coating has an effective photocatalytic activity and an ability to degrade dyes and remove some organic substances on the surface.