Corrosion Resistant and UV Durable PVDF-Co-HFP /Al2O3 Superhydrophobic Nanocomposite Coating for Aluminum

Abstract

The interest in superhydrophobic surfaces, which demonstrate high water-repellency, have recently increased dramatically because of their wide range of applications in many fields. The two major needed conditions to get a nanostructured superhydrophobic surfaces are the optimum surface roughness and low surface energy. In our present work, the fabrication process of a porous superhydrophobic coating on aluminum surfaces was achieved using a one-step electrospinning technique. The wettability properties of the prepared coating was inspected by measuring the water contact (WCA) and sliding angle (WCAH) before the addition of Al2O3 nanoparticles (150±2.9 and 6.25±1) while the measured WCA and WCAH after addition of nanoparticles was found to be 152±0.59 and 5±2.5, respectively. The wettability of the prepared coatings was inspected also after being irradiated with strong ultraviolet (UV) radiation of 1.5 W/m2 at a high temperature of 70 °C for 64 h. In fact no big difference was noticed after the UV test with respect to the wettability properties. The morphology of the superhydrophobic coating was studied using scanning electron microscope (SEM) coupled with energy dispersive X-ray (EDX). It shows the formation of a beaded fiber structure. Furthermore, Fourier transform infrared (FTIR) spectroscopy was used to check the nanocomposite coating before and after irradiation with UV. The surface roughness of the composite materials were measured using atomic force microscope (AFM). The corrosion behavior of the superhydrophobic nanocomposite coating was evaluated by the electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization in 3.5% NaCl. The results have shown that new nanocomposite coating exhibits a very high corrosion resistance.