Zwitterionic Cellulose Nanocrystals/Deacetylated Chitin Nanofiber Combined with SiO2 Hybrid Coatings: An Innovative Approach to Marine Antifouling

Marine biofouling poses many hazards to human activities. The introduction of zwitterionic agents as green and sustainable antibacterial agents into antifouling coatings exhibits excellent performance. In this work, cellulose nanocrystals (CNCs) and deacetylated chitin nanofibers (DECHNs) were cross-linked through electrostatic interactions, and hydrophobic SiO2 was used as the coating curing agent to prepare CNC/DECHN@SiO2 zwitterionic marine antifouling coatings. The results showed that when the proportion of CNCs components was 50%, the coating exhibited a 93% antibacterial rate and an 88% antialgae rate. In actual marine environment testing, the comprehensive resistance to marine biofouling reached 93% within 60 days. Our research introduces two natural components with opposite charges to construct zwitterionic complexes, innovatively applying them directly as antifouling agents in coatings. This work not only provides a solution for replacing toxic antifouling agents but also offers new ideas for using zwitterionic polymers directly as antifouling agents.