Robust superhydrophobic surface with reinforced skeletons for corrosion protection

A superhydrophobic surface on AA3003 with a structure consisting of microrods and nanosheets was fabricated via a chemical etching approach combined with modification by stearic acid alcohol solution. Etching time, temperature and concentration were adjusted to optimize surface topographies and wettability. The optimized surface exhibited a static contact angle of ~167° and a sliding angle of ~1°. The surface structure consisting of microrods and nanosheets was responsible for the superhydrophobicity, the formation mechanism of which was discussed in detail. The morphology of the Al alloy surface after deep etching indicated that the intermetallic phases had a strong pinning effect, providing reinforced skeletons for the superhydrophobic surface. The upright nanosheets trapped air, inducing excellent superhydrophobicity. Mn oxide was formed on the surface after the etching treatment, which caused a brown coloration. This process provides an environment-friendly and low-cost strategy to fabricate durable and corrosion-resistant superhydrophobic surfaces on large-scale substrates, which could potentially be used in various indoor applications.