A facile route to obtain binary micro-nano roughness on composite coating surface

Binary micro-nano rough morphology or structure shows a significant influence on hydrophobicity and icing-resistivity of the surface of coating materials. The leading cause for the classic Cassie state superhydrophobicity is the high area fraction of micro/nano air mattresses being in direct contact with a measured droplet. In this work, the dependence of static hydrophobicity on weight content of commercial surface-hydrophobicity-modified nano-silica in fluoropolymer based composite coatings has been investigated in detail via detecting static water contact angle (CA). It was found that elevating the weight content of hydrophobic nano-silica could contribute to a higher surface roughness, a more compact binary micro-nano morphology and a larger area ratio of air mattresses due to a stronger hypothesized phase separation. As a result, the remarkably improved water CA of composite coatings far higher than the neat polymer coating was observed relying on coating composition. Fortunately, the maximum static water CA of 167° was obtained in composite coating loaded with 50 wt% of hydrophobic nano-silica. For gaining the desired high comprehensive performances, it was advised to introduce 30 wt% of nano-filler into polymer. This work might open a facile route to achieve the promising superhydrophobic and anti-icing materials