Rapid one-step electrodeposition of robust superhydrophobic and oleophobic Ni coating with anti-corrosion and self-cleaning properties

Abstract

Superhydrophobic coatings as a surface modification method for copper substrates can improve their corrosion resistance and self-cleaning properties to extend their many industrial applications. A rapid one-step electrodeposition process was used to fabricate superhydrophobic nickel coatings with a hierarchical structure on copper substrates. Various surfaces with mushroom-like structures were obtained by adjusting the deposition voltage. The chemical composition of the coatings was nickel and nickel myristate. Contact angle measurement with three different liquids was performed to evaluate the surface energy of the coatings according to the Wu equation. All coatings were highly oleophobic representing high contact angles up to 172.3° and facile droplet rolling off. The effect of voltage on the distribution of clusters has led to different results for contact angle and corrosion performance. The highest charge transfer resistance (2370 kΩ·cm2) was obtained at an applied voltage of 35 V due to the uniform dispersion of pores and clusters. The coatings were highly durable as proved by EIS measurements in 3.5 % NaCl solution and aging in the air, which at the end of the period still had contact angles higher than 120°. The self-cleaning properties of the obtained surfaces were excellent due to the low surface energy and trapped air cushions.