Sol-gel-based bioinspired superhydrophobic self-cleaning and anticorrosive coating on metal surface

Corrosion on metallic surfaces is a great challenge suffered by humans in today’s world. In this study, a bioinspired hydrophobic coating based on nanosilica and zirconia was developed and characterized, showing a high contact angle, strong self-cleaning ability, and markedly enhanced corrosion resistance. Atomic force microscopy and scanning electron microscopy provided additional evidence of the nanostructures on coated metal, which give them their hydrophobic properties. Silica zirconia hexamethyldisilane (HMDS) modified coating showed a great water contact angle and hysteresis of 148° and 7°, respectively. The stability or adhesion of coatings was confirmed by tape and pH tests. The coatings were found to be stable in all pH solutions. Even after 5 days’ time there was no effect on coated metals; however, on uncoated metal, the corrosion process had already started. Furthermore, the anticorrosive behavior of coated metals was determined by the electrochemical impedance spectroscopy technique, and a Nyquist plot was plotted for coated and uncoated samples, thus confirming the efficacious anticorrosion mechanism exhibited by coatings by creating a physical diffusion barrier due to air entrapment on coated metal. Great corrosion resistance was offered by coatings of silica and zirconia modified by HMDS and trimethyl octylsilane.