Hydrophilic Cations and Hydrophobic Isoborneol-Based Amphiphilic Nanoparticles for Synergistic Marine Antifouling

Abstract

Natural antifoulant borneol was combined with a hydrolyzable cationic ester to develop amphiphilic copolymer poly(lauryl methacrylate)-b-poly(carboxybetaine methacrylate ester-co-isobornyl methacrylate) (PLMA-b-P(CBMAE-co-IBOMA)). Taking advantage of the zwitterionic groups resulting from the hydrolysis of CBMAE and the stereochemical antibacterial property of isobornyl, we synthesized a copolymer that exhibited a significantly higher bactericidal rate. We found that nanoparticles with equal block numbers of CBMAE and IBOMA achieved the highest bactericidal rate, with 2 h contact-killing rates of 88.38% and 84.34% against Escherichia coli and Staphylococcus aureus, respectively, implying the synergistic effect of the hydrophilic CBMAE moiety and hydrophobic isobornyl moiety in the structure-switchable amphiphilic copolymer. Moreover, the coatings are capable of resisting marine biofouling for up to ∼150 days in a flourishing season of marine organisms.