Synthesis of E‐54‐Based Quaternary Ammonium Salt and Its Efficacy in Antifouling Performance of Marine Coating

ABSTRACT Marine biofouling poses a threat to marine facilities. In this work, a quaternary ammonium salt (E54‐QAS) was synthesized from triethylammonium hydrochloride and epoxy resin E‐54, which was then incorporated into a polyurethane (PU) prepolymer to fabricate an antifouling coating. The coating exhibited a bonding strength as high as 3.12 MPa and impact resistance of 90 kg as well as excellent antibacterial efficiency against Pseudomonas aeruginosa at an E54‐QAS content of 4.2%. Moreover, the antimicrobial efficacy of the coating remained above 99% after 3 months of immersion. The optimized formulation effectively inhibited diatom growth and adhesion, demonstrating superior antifouling performance and long‐term efficacy. The coating shows promising application in maritime vessels, nuclear power plants, and offshore platforms, offering an effective solution to marine biofouling issues.