Superhydrophobic membranes on metal substrate and their corrosion protection in different corrosive media

Superhydrophobic membranes with different surface morphologies and chemical compositions were prepared by sol-gel method. The superhydrophobicity on the surface with high roughness is ascribed to the biomimetic structure of the lotus, while the wetting behavior observed on the relatively smooth surface is attributed to the air bubbles trapped in the asperities and the discontinuous contact line. Moreover, it has been demonstrated that the humid air test is required to assess the tendency occurrence of electrolyte film and that the Tafel plots and the water repellency are not adequate to evaluate the corrosion resistance in the practical environment. Compared with the surface chemical compositions, the surface morphology plays more important role in anti-corrosion ability in humid air. (C) 2014 Elsevier B.V. All rights reserved.