A switchable zwitterionic ester and capsaicin copolymer for multifunctional marine antibiofouling coating

In this work, a multifunctional marine antibiofouling coating was prepared by covalently grafting switchable zwitterionic ester and capsaicin copolymers onto the polydimethylsiloxane (PDMS) network in a one-pot reaction. Zwitterionic esters could kill bacteria via their positive charge and release dead bacterial cells after hydrolysis to antifouling zwitterionic moieties. Meanwhile, chemically conjugated capsaicin molecules could also be sustainedly released via hydrolyzation to repel marine organisms. Compared with the pristine PDMS matrix, the hydrolyzed coating reduced protein adhesion by 88.5%, bacterial adhesion by 99.0%, and diatom adhesion by 99.5%. The adhesion force of pseudo barnacles was reduced by 72.4%. Marine field tests in the Yellow Sea further confirmed that the coating possessed excellent antibiofouling ability for at least 261 days. This study presents a promising strategy for the development of eco-friendly high-efficiency marine antibiofouling coatings.