Photocatalytic TiO2/PDMS coating to drive self-cleaning: a facile approach for anti-stain silicone rubber surfaces

Abstract

The formation of a robust photocatalytic hydrophobic hybrid coating on a polymer substrate via a simple process, such as dip-coating, is useful for practical applications but still challenging. In this study, the photocatalytic coating is prepared by nano-TiO2 hydrosol and polydimethylsiloxane (PDMS), which has both photocatalytic and hydrophobic properties. The as-prepared TiO2/PDMS coating can be applied on silicon rubber directly via a dipping process. FTIR, XPS, and HRTEM analysis showed that the interaction between PDMS and nano-TiO2 occurred via generated Ti-O-Si bonds. The photocatalytic activity test performs that this coating can remove organic pollutants methylene blue (MB) dissolved in the water. Meanwhile, the coating can degrade the organic dye stained on the silicon rubber surface under UV irradiation. The water contact angle test shows that the hydrophobicity of the TiO2/PDMS coating is stable under UV irradiation for over 60 h, which means the existence of TiO2 will not break the PDMS in the hybrid coating. Also, the hybrid coating can keep both hydrophobicity and photocatalytic activity even after pre-irradiation treatment. These results show that the as-fabricated hybrid coating has promising applications for functionalizing silicone rubber surfaces to endow them with photocatalytic activity to degrade organic pollutants on surfaces both in ambient and aqueous environments, and the hybrid coating has potential stable self-cleaning function.