Three-level hierarchical superhydrophobic Cu–Zn coating on a steel substrate without chemical modification for self-cleaning property

Abstract

A superhydrophobic Cu–Zn coating was fabricated on a steel surface by facile one-step electrodeposition, without being chemically modified by a low surface energy material. It was noted that three-level hierarchical structures, just like the surface morphology of a lotus leaf, were formed on the Cu–Zn coating surface via scanning electron microscopy (SEM) images. The water contact angle of the prepared Cu–Zn coating surface was 153.40°, and the sliding angle was less than 10°. From the aspect of chemical composition, it was characterized to confirm that the oxidation of Cu and Zn, and oxygen adsorption were the reasons for the superhydrophobicity. In terms of the surface morphology, based on the classical Wenzel and Cassie models, an idealized three-dimensional (3D) model was fabricated to demonstrate the rationality of the superhydrophobicity without chemical modification. Moreover, this three-level hierarchical Cu–Zn coating had stable superhydrophobicity, excellent self-cleaning properties, and stability.