Seawater-triggered self-renewable amphiphilic coatings with low water swelling and excellent biofilm prevention properties

Amphiphilic antifouling coatings have the potential to revolutionize the field of eco-friendly antifouling coatings, which are still beset by the drawbacks of instability, complex procedures and water swelling. Herein, we construct seawater-triggered amphiphilic coatings with self-renewable capabilities in seawater via the facile casting of a physical mixture of a hydrolyzable polymer (PTMH), hydroxyl-terminated polydimethoxysilane and an isocyanate crosslinker. The hydrophilic chain is generated in situ from PTMH at the coating/seawater interface and thus ultimately mitigates its seawater swelling. The hydrolyzability of PTMH and the degradation of the urethane crosslinking bond endow the coating with self-renewable properties. Owing to the appropriate hydrolysis rate of PTMH, its water absorption is lower than 3 wt% for 30 days of seawater submersion. Notably, the biofilm prevention capability of the coatings is excellent, outperforming that of polydimethoxysilane-based polyurethane and self-polishing polymers in real sea conditions. We envision that this work will provide a new avenue to design microphase separation-based antifouling coatings for practical applications.