Hydrophobic photocatalytic composite coatings based on nano-TiO^sub 2^ hydrosol and aminopropyl terminated polydimethylsiloxane prepared by a facile approach

A facile approach was adopted to fabricate hydrophobic photocatalytic composite coatings from nano-TiO2 hydrosol and aminopropyl terminated polydimethylsiloxane (NH2-PDMS). A strong interaction bewteen nano-TiO2 and polymers was verified by FTIR and XPS. The photocatalytic activity of the composite coatings was about the same as that of superhydrophilic photocatalytic coating according to the degradation activity of methylene blue (MB). The composite coatings were hydrophobic with water contact angles (WCA) around 120°, which remained stable over 318 h against UV irradiation. The discoloration of contaminated MB on coatings was performed under outdoor exposure indicating quicker color bleaching of MB on composite coatings than that on the controls. The advantages of combining hydrophobic and photocatalytic properties would offer a potential solution as self-cleaning surfaces in various applications.