Degradation-Function Coupling in Eugenol-Functionalized PLGA Polyurethanes for Antifouling Interfaces

The development of biodegradable antifouling coatings represents a promising route to environmentally compatible marine protection. However, most polyester-based systems exhibit limited interfacial evolution and a poor long-term biofouling resistance. Here, we report poly(lactic-co-glycolic acid) (PLGA)-based polyurethane (PU) coatings that bear covalently tethered eugenol (EU) side groups (PLGA–PU-EUx), designed to couple hydrolytic degradation with interfacial bioactivity. Compared with PLA-based analogues, the PLGA–PU-EUx coatings show greater mass loss, lower water contact angles during seawater immersion, more evident chemical and morphological evolution, and markedly enhanced inhibition of marine bacteria (Micrococcus luteus) and diatoms (Navicula incerta). At 15 wt % EU, diatom inhibition exceeds 95%. Leachate analysis indicates that freely dissolved EU-related species are highly limited under the tested conditions, while zebrafish embryo assays show no obvious acute developmental toxicity. These findings establish degradation-function coupling as a general strategy for designing durable and environmentally benign antifouling interfaces.