Fabrication of superhydrophobic surface by hierarchical growth of lotus-leaf-like boehmite on aluminum foil

Hierarchical growth of boehmite film on the aluminum foil was carried out via a facile solution-phase synthesis route. The resultant film is composed of three-dimensional microprotrusions assembled from well aligned nanoneedles. Such dual scale micro-/nanostructures are highly similar with those of lotus leaves. The resultant surface after hydrophobization exhibits a water contact angle of 169° and a sliding angle of ∼4° for a 5 μL droplet, which is ascribed to the combination of the dual scale roughness at the micro- and nanometer scale and the low surface energy of stearic acid coating. The obtained film possesses relatively good adhesion to the aluminum substrate and keeps superhydrophobicity after the ultrasonic treatment or long-term storage in spite of the partial loss of it superhydrophobic ability after abrasion test.

Graphical abstractThe superhydrophobic and non-sticking surface with dual scale roughness has been fabricated by means of heterogeneous growth of lotus-leaf-like boehmite on aluminum foil for the first time.Figure optionsDownload full-size imageDownload high-quality image (82 K)Download as PowerPoint slideResearch highlights► Lotus-leaf-like boehmite was fabricated on the Al surface for the first time. ► The surface possesses dual scale roughness (nanoneedles on the microprotrusions). ► The surface exhibits superhydrophobic and non-sticking behaviors. ► The dual scale roughness accounts for the excellent superhydrophobicity.