Dual-functional Ag-MOF nanoparticle composite coatings for enhanced anticorrosion and antibacterial performance on aluminum alloys

Ag-MOF nanoparticles were successfully synthesized using a convenient and mild liquid-phase route, employing AgNO 3 , imidazole, and trimesic acid (H 3 BTC) as a unique multifunctional organic ligand, which, unlike conventional Ag-MOF systems based on simple imidazole, enables the formation of a more stable and highly coordinated framework structure, thereby facilitating uniform particle distribution and improved functionality. This study investigated its antibacterial mechanism and effectiveness when the nanoparticles were integrated into acrylic coatings on AA2024 aluminum alloy substrates. The synthesized Ag-MOF particles demonstrated significant antibacterial activity, which is attributed to the sustained release of Ag + ions and its stable dispersion within the coating matrix. The reduction in E. coli and S. aureus populations was observed to be 95.9 % and 87.2 %, respectively. Benefiting from both the physical barrier effect and the controlled delivery of corrosion inhibitors, the coating exhibits improved durability against corrosion. Additionally, a bifunctional composite coating, featuring a cerium-doped sol-gel application as a bottom layer, was prepared to further improve antibacterial and anticorrosion properties. Electrochemical tests confirm that the composite coating shows the higher impedance modulus and the smaller corrosion current density across the low-frequency domain than neat coating, which was the contribution of the combined action of the inhibitor and the coating's barrier properties. According to the electrochemical impedance after 7 days immersion, the composite coating showed superior corrosion resistance comparing to the neat acrylic coating during immersion of seven days.