Silicone Elastomer with Self-Generating Zwitterions for Antifouling Coatings

Silicone elastomer-based fouling release coatings have been gaining increased attention in marine antibiofouling. However, the lack of fouling resistance limits their application. Introducing a zwitterionic polymer into silicone enhances its fouling resistance, but their incompatibility makes this challenging. In this work, a silicone elastomer with zwitterionic pendant chains has been prepared by grafting a telomer of tertiary carboxybetaine dodecafluoroheptyl ester ethyl acrylate (TCBF) and 3-mercaptopropyltriethoxysilane to the bis-silanol-terminated poly(dimethylsiloxane) (PDMS). The fluorocarbon groups drive the telomer onto the surface in the film formation process, while the TCBF groups hydrolyze and generate zwitterions on the surface, which is confirmed by attenuated total reflection infrared spectra analysis and water contact angle measurements. Bioassays using marine bacteria (Pseudomonas sp.) and diatoms (Navicula incerta) demonstrate that the antifouling efficacy is improved as the telomer content increases. The bacteria and diatom adhesion decreases by 95 and 81%, respectively, for the PDMS with 30 wt % telomer compared with the unmodified PDMS control. Meanwhile, the fouling release performance of PDMS is maintained with a pseudobarnacle removal strength of ∼0.1 MPa. This work provides a facile way to fabricate efficient silicone-based antifouling coatings.