Corrosion resistance of superhydrophilic and superhydrophobic TiO2/epoxy coatings on AISI 316L stainless steel

Superhydrophilic and superhydrophobic TiO2/epoxy coatings were prepared with as-received TiO2 and fluoroalkylsilane (FAS) functionalised TiO2 nanoparticles and successfully applied to the surface of AISI 316L stainless steel.The wetting properties of the coatings were confirmed with static contact-angle measurements.The corrosion performance of the investigated coatings was studied by electrochemical impedance spectroscopy (EIS).The open-circuit impedance spectra of the AISI 316L stainless steel, the epoxy-coated AISI 316L, the as-received TiO2/epoxy coating on AISI 316L and the FAS-TiO2/epoxy coating on AISI 316L were measured in simulated physiological Hank's solution.Bode plots and Nyquist diagrams were used to evaluate the corrosion properties of the investigated coatings.The results show the enhanced corrosion resistance of surface-modified stainless steel, especially in the case of the superhydrophobic FAS-TiO2/epoxy coating.