Fabrication of Functional Biobased Epoxy Coatings via Cinnamic Acid Grafting: Synergistic Antibacterial, Antifouling, UV-resistant, and Superhydrophobic Properties

Effective antifouling coatings are critical for protecting marine infrastructure from biofouling and environmental degradation; however, achieving long-term antifouling performance along with environmental stability remains a major challenge. In this study, a multifunctional bio-based epoxy coating is developed by integrating a dual-action antifouling system. Cinnamic acid (CA), which is known for its antibacterial and UV-shielding properties, was chemically grafted into ethylene glycol diglycidyl ether (EGDE) to provide intrinsic antifouling and anti-UV functions. Simultaneously, the KH560-modified silica aerogel was incorporated to create a dense hydrophobic surface that repels microorganism adhesion. The resulting coating exhibited a superhydrophobic contact angle of 154.3°, an ultralow surface energy, and exceptional resistance to protein and algal adhesion. Additionally, it achieves 99% bactericidal efficiency against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) while maintaining high transparency and ease of processing. These results highlight a promising strategy for designing durable and ecofriendly antifouling coatings suitable for demanding marine environments.