Fabrication of Microgel-Functionalized Metal–Organic Framework Composite Polyurethane/Hydrogel Coatings with Enhanced Antifouling Performance

Antifouling coatings are a key component of marine antifouling strategies, offering a competitive solution to combat biofouling. However, many coatings face significant limitations stemming from insufficient mechanical properties and weak antibacterial performance. Herein, the composite coatings (PMETAC@Ag-MOF/PU/GEL) were prepared by integrating polyurethane/hydrogel (PU/GEL) composites as the polymer matrix and microgel-functionalized metal-organic frameworks (PMETAC@Ag-MOF) as nanofillers. The prepared composite coatings PMETAC@Ag-MOF/PU/GEL combine the excellent mechanical properties of polyurethane with the hydratability of hydrogels and demonstrate enhanced mechanical properties, swelling resistance, and lubrication compared to the original coating. Importantly, it effectively reduces microbial attachment and improves the corrosion resistance of the coating through the slow release of Ag+, achieving over 99% bacterial elimination and reducing microalgae attachment by 98%. The improved dispersibility provided by methacryloxyethyltrimethylammonium chloride (METAC) of hydrogels, coupled with the protective film formed by the 2-mercaptobenzothiazole (MBT) of MOFs, significantly improve corrosion resistance of the coating by creating a barrier between the substrate and corrosive environment. Notably, MBT, as a ligand, is incorporated into the structure of MOFs, moderating the release of the antifouling agent and extending the coating's corrosion resistance over time.