Fabricating Superhydrophobic Surfaces via a Two-Step Electrodeposition Technique

This work presents a template-free electrochemical route to producing superhydrophobic copper coatings with the water contact angle of 160 +/- 6 degrees and contact angle hysteresis of 5 +/- 2 degrees. In this technique, copper deposit with multiscale surface features is formed through a two-step electrodeposition process in a concentrated copper sulfate bath. In the first step, applying a high overpotential results in the formation of structures with dense-branching morphology, which are loosely attached to the surface. In the second step, an additional thin layer of the deposit is formed by applying a low overpotential for a short time, which is used to reinforce the loosely attached branches on the surface. The work also presents a theoretical analysis of the effects of the fabrication parameters on the surface textures that cause the superhydrophobic characteristic of the deposit.