Fabrication of Ag-Alginate/MXene Nanosheet Composite Coatings for Enhanced Antifouling Performance

Marine biofouling is a common issue that concerns safety, cost, and ecosystem stability. Alginate, a commonly used filler in functional coatings and membranes, is also widely researched for biomedical applications. This study presents a novel approach for developing advanced self-polishing coatings by combining MXene nanosheets with sodium alginate (SA) and silver ions (Ag⁺). SA was uniformly deposited onto the MXene surface via oxidative copolymerization of dopamine and dopamine-sodium alginate (DA-SA), followed by the loading of Ag⁺ through ion exchange to obtain the MXene-SA-Ag composite. The resulting functionalized MXene nanosheets─MXene-SA and MXene-SA-Ag─showed enhanced antifouling performance due to the synergistic effect of the components. Specifically, the antibacterial efficiency of MXene-SA against the E. coli was 94.5%, while MXene-SA-Ag exhibited antibacterial rates exceeding 99% for both E. coli and S. aureus. The composite self-polishing coatings were then fabricated by incorporating functionalized MXene nanosheets with presynthesized self-polishing (SP) resin. The obtained nanocomposite coatings presented enhanced hydrophilicity, multifaceted antifouling mechanisms, and outstanding antifouling performances. The removal rates were above 90% against both bacteria and microalgae. Compared to conventional coatings, this novel design offers a copper-free alternative with remarkable antifouling performance.