Rapid fabrication of zwitterionic coating on 316L stainless steel surface for marine biofouling resistance

Zwitterionic polymers are considered as nontoxic fouling-resistant materials, and have been widely studied in recent years. However, the immobilization of zwitterionic polymers on metal surfaces still suffers from the complicated and time-consuming procedures. In this work, a zwitterionic polydopamine/poly(sulfobetaine methacrylate) (PDA/PSB) coating on 316L stainless steel surface was fabricated by simply immersing in a mixed solution of dopamine, sulfobetaine methacrylate (SB) and oxidants for 30 mins. The anti-fouling performance of PDA/PSB coating was evaluated in terms of organic molecules (protein and polysaccharide) adsorption and microbes (Gram-negative bacterium, Gram-positive bacterium and diatom) adhesion. The results showed that the PDA/PSB coating inhibits the adsorption of BSA and sodium alginate, and further reduces the adhesion of Pseudomonas aeruginosa, Bacillus subtilis and Navicula sp. by more than 99% in 24 h. This research provides an important inspiration for the practical application of zwitterionic polymers in the field of marine anti-fouling.