Functional Antifouling Hydrogel Surface Engineering: Insight into Mechanisms, Interfacial Regulation and Marine Protection
Marine biofouling, the attachment and accumulation of marine organisms on submerged anthropogenic structures, imposes substantial operational and environmental burdens on shipping, offshore engineering, and marine ecosystems. Traditional antifouling strategies, including mechanical scrubbing, ultrasonic removal, and heavy-metal ion electrolysis, are constrained by high cost, operational complexity, and ecological hazards. Antifouling coatings have emerged as a cost-effective alternative, yet early formulations based on asphalt, tar, and lead posed environmental risks, and tributyltin (TBT) self-polishing coatings were globally banned in 2008 due to toxicity and bioaccumulation. Hydrogel coatings have attracted considerable interest because of their biocompatibility, low toxicity, and environmentally friendly characteristics. This review synthesizes the application of hydrogel coatings in marine antifouling, systematically analyzing molecular design and network structure regulation achieved through various crosslinking strategies, and elucidating antifouling mechanisms. It summarizes antifouling performance in laboratory and field environments, examines composite and multifunctional hydrogel coatings for enhanced overall performance, and discusses developmental potential. Current limitations of hydrogel antifouling coatings are analyzed and future research directions proposed, intending to provide theoretical insights for effective and environmentally responsible marine antifouling solutions.