Synergistic antibacterial and anti-adhesion effects of zinc-based eugenol-modified composite coatings for marine antifouling applications

Marine biofouling severely impedes the development of marine engineering, while existing coatings suffer from inadequate environmental compatibility and insufficient long-term efficacy. To address these limitations, this study reported the fabrication of eugenol-functionalized ZnO (ZnO@Eug) via a one-pot hydrothermal approach. Subsequently, ZnO@Eug was further modified with hexadecyl trimethyl ammonium bromide (CTAB) via electrostatic interactions to yield the ZnO@Eug@CTAB composite filler, which was then incorporated into a polydimethylsiloxane (PDMS) matrix to fabricate the ZnO@Eug@CTAB/PDMS (ZECP) composite coating. Benefiting from the synergistic effects of Zn 2+ , eugenol, and CTAB, the ZECP coating achieved 100 % antibacterial efficiency against E. coli after 24 h of co-cultivation with bacterial suspensions. Anti-algal and anti-marine organism experiments demonstrated that the ZECP coating effectively suppressed Chlorella colonization and prevented the attachment of conchs. Moreover, the ZECP coating displayed controlled Zn 2+ release behavior while maintaining a high water contact angle of 121° and low surface free energy of 20.2 mN·m −1 , thereby contributing to its long-term antifouling performance. Based on the dual functions of active antibacterial and anti-marine organism adhesion, the ZECP coating can be applied in the field of environmentally friendly marine antifouling coatings.