A Facile Method for Fabrication of Hybrid Hydrophobic-Hydrophilic Surfaces on Anodized Aluminum Template by Electrophoretic Deposition

Abstract

Within the last decade, hybrid hydrophobic-hydrophilic surfaces have aroused considerable interest due to potential applications in a wide range of industries, including power generation, desalination, and oil-water separation. In this paper, a facile method for the fabrication of hybrid surfaces is presented, which can be extended to industrial scale. In the first step, the Aluminum (Al) substrates are anodized to produce a hydrophilic Anodic Aluminum Oxide (AAO) template. Following that, the Electrophoretic Deposition (EPD) method is employed to fill nanoscale pores of the anodized template with hydrophobic silica nanoparticles. The porosity of the AAO and deposition rate in both anodizing and EPD processes made a notable contribution to hybrid surface finishing. Also, Water Contact Angle (WCA) measurements are conducted after each experiment step to examine the wettability mode of samples. Results revealed that by increasing surface porosity up to roughly 63%, surface wettability mode shifts to the hydrophobic region. It is also demonstrated that adjustment of suspension properties, including zeta potential and electrical conductivity, can promote superhydrophobicity on the surface by affecting the deposited layer roughness. Herein, the best water repellency was achieved for a zeta potential of +48.1 μS. The fabricated hybrid surface, which represented WCA within 93.4° to 108.8° on average, offers promising performance in the exposure to humid air and helps enhance the condensation phase change process.