From copper to curcumin: the role of fillers in the development of sustainable marine antifouling polymer composites.

Marine biofouling remains a persistent global challenge, causing severe deterioration of offshore infrastructures and marine vessels, which results in significant economic losses and ecological concerns. Conventional antifouling strategies relying on toxic biocides (copper, organotins) face stringent regulatory prohibition due to ecosystem devastation, creating an urgent demand for sustainable alternatives. Here, we critically evaluate emerging bio-based antifouling technologies, demonstrating that nanocomposite-polymer systems and natural bioactive integration offer viable pathways toward toxin-free marine protection with strategies based on metal oxides and graphene oxide nanocomposites delivering up to 97% macrofouling reduction, and biodegradable polymer matrices (chitosan, alginate, polylactic acid) combined with natural fillers exhibited copper-comparable efficacy without environmental persistence. Among them, polylactic acid-curcumin composites (FDA-approved biodegradable polymers with plant-derived bioactives) exhibit high efficiency, being particularly effective and eliminating up to 99.9% of bacterial species. However, their uptake has so far been limited by critical knowledge gaps, particularly a lack of comprehensive marine field validations against macrofouling communities, the absence of multi-year performance data, and incomplete environmental fate characterization, all of which prevent deployment. This paradigm shift from chemical to biological control could revolutionize maritime industries while safeguarding marine biodiversity and enabling sustainable blue economy expansion.