Facile fabrication of non-sticking superhydrophobic boehmite film on Al foil

A superhydrophobic boehmite film composed of dual scale microprotrusions has been fabricated on an Al foil via a facile solution-phase approach. The hierarchical microprotrusions are built up of leaf-like nanoplatelets and follow a heterogeneous nucleation, growth and aggregation mechanism. Steric acid molecules chemisorb onto the boehmite film in order to effect hydrophobization. The resulting superhydrophobic surface exhibits a water contact angle of 168° and a sliding angle of ∼2.1° for a 5 μL droplet. The combination of the dual scale roughness and the low surface energy coating accounts for the superhydrophobicity. The superhydrophobic surface has an excellent non-sticking behavior and exhibits anticorrosion in an electrolyte solution, which should be critical to the applications of Al materials in engineering.