Fabrication of repairable anti-corrosive superhydrophobic surfaces with micro-nano structures by ultrasonic cavitation

Abstract

We proposed a novel superhydrophobic fabrication method based on ultrasonic cavitation. The collapse of cavitation bubbles eroded the surface to form a microstructure with high roughness. SiO2 nanoparticles were then effectively anchored on the surface using cavitation jets to form a micro-nano composite structure. The superhydrophobic performance was evaluated on the basis of the water contact angle (WCA). The proposed method achieved robust superhydrophobic property, and the WCA of copper, brass and 304 stainless steel substrates exceeded 153.3°. The morphology and composition of the superhydrophobic surfaces were characterized using scanning electron microscopes and Fourier transform infrared, respectively. Results revealed that the SiO2 particles were uniformly dispersed, and a flaw-free state was obtained by the surface. The samples exhibited excellent anti-corrosive durability during ultraviolet and outdoor testing and immersion in different corrosive solutions. The cavity generated by the cavitation erosion can be used as a container to suppress the loss of effective components. The micro-nano double layer structure was retained, and the WCA can be restored to the original level through functionalization again to give low surface energy. The prepared superhydrophobic surface was repairable. In addition, the WCAs of the copper foam and sponge were 157.0° and 159.6°, respectively.