On Hydrophobicity, Superhydrophobicity and Icephobicity of Etched Aluminum Surfaces

Several hydrophobic and superhydrophobic aluminum surfaces were prepared with a three-step process that includes chemical etching, a treatment in hot water and a further coating with fluoroalkysiloxane (FAS). By varying the concentration of the etchant, the immersion time in the etchant and the boiling time, surfaces characterized by different roughness were obtained, with a wettability ranging from hydrophobic to superhydrophobic values. The icephobic properties were tested and the results reveal important differences among samples, related to the roughness of the surface and the etching and boiling treatment processes.