UiO-66 and UiO-66-NH2 membranes-based superhydrophobic coatings for enhanced corrosion protection

Fabricating metal-organic frameworks (MOFs) membranes directly onto metal surfaces as anticorrosive coatings is a feasible approach for the application of MOFs in corrosion protection. The MOFs membranes with specific organic groups can be further customized as versatile platforms for developing various functional coatings. Herein, UiO-66 and UiO-66-NH2 membranes are synthesized onto aluminum surfaces through a polydopamine-assisted method, which are then grafted with superhydrophobic molecules of perfluorodecyltriethoxysilane (PFDTES). The -COOH groups in UiO-66 and -COOH/-NH2 groups in UiO-66-NH2 can serve as firm anchor sites for covalently grafting with PFDTES, enabling robust superhydrophobicity of the as-prepared coatings. The superhydrophobic surfaces exhibit water repellency (water contact angle of ∼165o), chemical (pH and salinity) and wear-resisting robustness, and long-term service durability. They also perform decent anti-fouling, self-cleaning, and anti-icing properties. Notably, sustainable corrosion protection can be provided by both coatings during immersion in saline solution (3.5 wt% NaCl) for one month and during a two-week salt spray test. Compared with UiO-66, the -NH2 groups on UiO-66-NH2 as extra grafting sites for firmer immobilization of more PFDTES molecules facilitate more durable superhydrophobicity and corrosion protection. We believe that this work could offer valuable insights into the multi-functional development of MOFs membranes-based coatings.