Rational fabrication of superhydrophobic surfaces with coalescence-induced droplet jumping behavior for atmospheric corrosion protection

Coalescence-induced droplet jumping behavior on superhydrophobic surfaces has a potential application in atmospheric corrosion protection by spontaneously removing the corrosive water film/droplets. However, the design guidelines for superhydrophobic surfaces to realize coalescence-induced droplet jumping behavior remain lacking, and the antifogging ability of droplet jumping behavior for atmospheric corrosion protection is unknown. Herein, two kinds of superhydrophobic surfaces, namely, the sheet-like structure superhydrophobic surface and the cluster-like structure superhydrophobic surface, were rationally fabricated over the copper substrate by the different solution-immersion process followed by the same hydrophobized treatment. First, the correlations of the microstructure and droplet jumping behavior of the two surfaces were studied, and a droplet jumping phase map that divided the jumping and non-jumping regions was formulated from the perspective of energy. The sheet-like structure superhydrophobic surface with a higher contact angle and a lower surface roughness is more favorable to droplet jumping behavior due to a lower solid/liquid contact area and interfacial adhesion. Second, the antifogging ability of droplet jumping behavior for atmospheric corrosion protection was experimentally demonstrated. Comparatively, the sheet-like structure superhydrophobic surface presents a superior anti-corrosion performance due to droplet jumping-induced wetting transition. This work offers design guidelines for superhydrophobic surfaces to realize coalescence-induced droplet jumping behavior in selfcleaning, anti-icing/anti-frosting, and condensation heat transfer enhancement applications, and provides insights into designing efficient technologies in the application of atmospheric corrosion protection.