Preparation of a temperature-sensitive superhydrophobic self-cleaning SiO2-TiO2@PDMS coating with photocatalytic activity

In this paper, SiO2-TiO2 composite particles were prepared by loading nano-TiO2 onto the surfaces of amorphous SiO2 microspheres, which were then modified with PDMS to obtain a SiO2-TiO2@PDMS ternary compound. The photocatalytic performance of SiO2-TiO2@PDMS and the wettability of the coated surface were tested and characterized. Moreover, the effect of microstructure and composition of SiO2-TiO2@PDMS on its properties was studied. The results showed that SiO2-TiO2@PDMS possessed a certain degree of photocatalytic activity and the coating was almost superhydrophobic. Furthermore, the wettability and adhesion to water droplets of the SiO2-TiO2@PDMS coating were affected by the heat-treatment temperature; the mechanism of the above phenomena was also analysed. Moreover, the as-prepared coating exhibited excellent repellent effects towards acid (pH = 2), alkaline (pH = 11), and organic dye droplets. A mechanically damaged coating maintained its liquid repellence, indicating that the good mechanical stability of the coating. The superhydrophobicity of the as-prepared coating did not decrease after UV irradiation for 8 h, illustrating that the as-prepared coating had a great UV irradiation resistance. In addition, the as-prepared coating was environmentally friendly and free of fluorides and is therefore suitable for practical applications.

Automated summary

SiO2-TiO2@PDMS ternary compound with certain photocatalytic activity and superhydrophobicity was prepared in this study, showing excellent repellent effects towards different liquid droplets. The coating exhibited good mechanical stability and UV irradiation resistance, making it suitable for practical applications.