Fabricate of superhydrophobic POTS/ZIF-8@MAO composite coating on TC4 titanium alloy with anti-fouling and corrosion resistance properties

Although micro-arc oxidation (MAO) coatings improve the mechanical properties of titanium alloys, their porous structural defects tend to act as pathways for corrosive agents and as adhesion sites for contaminants. In this study, a superhydrophobic coating was developed on TC-4 titanium alloy by combining in-situ hydrothermal synthesis of ZIF-8 with POTS surface modification, thereby forming a rough surface with low surface energy. The POTS/ZIF-8@MAO composite coating exhibits strong adhesion to the substrate through both physical and chemical bonding. Consequently, it demonstrates excellent chemical and thermal stability, maintaining a water contact angle (WCA) of 156.53° ±2.47° and a sliding angle (SA) of 6.32° ±1.16° even under extreme conditions. Due to its low water adhesion, the coating demonstrates significant self-cleaning ability against both solid and liquid contaminants. Electrochemical analysis reveals that it improves corrosion inhibition by up to 99% compared to pristine MAO-treated titanium alloy, providing an effective protective barrier for the substrate. This work proposes a promising strategy that may potentially expand the application scope of titanium alloys.