Preparation and properties of biomimetic superhydrophobic composite coating

A nanosilica (SiO2)/polyurethane (PU) micro-nanocomposite coating with similar surface structure as a lotus leaf was prepared using a simple spraying process. The formation mechanism and structural characteristics of the coating were analysed. The coating surface was also characterised via scanning electron microscopy. The influence of the contents of SiO2, PU, and organosilicon on the coating surface structure and contact angle was studied. The results showed that the coating surface had a similar micro-nanostructure as the lotus leaf surface. When the content of organosilicon was greater than 15%, the water contact angle of the coating and sliding angle were 158 and 3 degrees, respectively. This SiO2/PU micro-nanocomposite coating had super-hydrophobic properties and repeated use performance.