Self-healing superhydrophobic A-SiO2/N-TiO2@HDTMS coating with self-cleaning property

The superhydrophobic self-cleaning coatings with reversible adhesion to water droplets have attracted much attention due to the unique and wonderful self-cleaning performance. In this paper, amorphous SiO2 microspheres (A-SiO2) and nano-TiO2 particles (N-TiO2) were used to fabricate A-SiO2/N-TiO2 composites by wet grinding, and then they were modified with Hexadecyltrimethoxysilane (HDTMS) and sprayed onto the surface of substrate to obtain a A-SiO2/N-TiO2@HDTMS coating. The water contact angle (WCA) and contact angle hysteresis (CAH) of the coating were 157.2° and 2.7°, respectively. After UV irradiation, the WCA decreased to 140.9°, and water droplets stuck onto the coating surface even the coating was turned upside down. Significantly, the coating surface returned to its original superhydrophobic state after dark storage for 8 h, showing a self-healing property. Furthermore, methyl orange solution was degraded by the as-prepared coating under UV irradiation. Moreover, the as-prepared coating maintained its self-cleaning performance after being placed outdoors for 3 months, exhibiting the potential to be used outdoors for a long time. The as-prepared coating not only has excellent properties but also the advantages of environmental protection. Therefore, this research provides an advanced method to prepare self-cleaning coatings environmentally.