Fabrication and properties of n-SiO₂/m-SiO₂/PU superhydrophobic coatings

In order to eliminate the adverse effects of icing on the surface of mechanical devices such as power transmission cables and wind turbine blades due to low temperature, nano-silica (n-SiO₂) and micron-silica (m-SiO₂) modified by silane coupling agent were blended with a mass ratio of 5:1 and subsequently compounded with polyurethane (PU) to obtain n-SiO₂/m-SiO₂/PU superhydrophobic coatings. It is shown that the tight bonding of m-SiO₂ with PU avoids the cracking of the coating due to the agglomeration of n-SiO₂ and improves the stability of the coating. n-SiO₂ makes the surface of n-SiO₂/m-SiO₂/PU coating form a dense and rough structure, which increases the air-liquid contact area by trapping more air. The contact angle reached 158.10° at a low filling ratio(40 wt%), indicating that the prepared n-SiO₂/m-SiO₂/PU coating has excellent superhydrophobic properties. The superhydrophobic n-SiO₂/m-SiO₂/PU coating is very helpful in solving the low-temperature icing problem of outdoor power and wind equipment in rain and snow.