Influence of water adhesion of superhydrophobic surfaces on their anti-corrosive behavior

The water adhesion is important for superhydrophobic materials. Compared with considerable research on metal corrosion protection using superhydrophobic coatings, research involving the different water adhesion of superhydrophobic coating on its anti-corrosive behavior is neglected. Herein, superhydrophobic coatings with controllable water adhesion were successfully fabricated by spraying different percentages of hydrophobic SiO2 nanoparticles (NPs) on the Al substrate, and then the influence of water adhesion of superhydrophobic surfaces on their anti-corrosive behaviour was studied. The electrochemical test was carried out on the superhydrophobic surface with different water adhesion to reveal the influence of water adhesion on anti-corrosion capability. The results showed that the anti-corrosion was markedly influenced by the water adhesion of the superhydrophobic coating, and their corrosion resistance was varied in the order of low-adhesion > medium-adhesion > high-adhesion. Moreover, the superhydrophobic coating with the percentage of OTS-SiO2 = 100 possesses unexpected corrosion protection property with lower corrosion rate (CR) and higher polarization resistance (Rp). The corrosive current reduced and impedance modulus (Rct) increased with the decrease of adhesion. In addition, the anti-corrosion mechanism of superhydrophobic coatings with different adhesion was elaborated.