Polysiloxane-based block copolymers with marine bacterial anti-adhesion properties.

Di- and triblock copolymers based on tert-butyldimethylsilyl methacrylate (MASi) and poly(dimethylsiloxane) (PDMS) macro-RAFT agents were synthesized resulting in copolymers with predictable molar masses and low dispersities (Đ < 1.2). The block copolymers exhibited two glass transition temperatures, corresponding to the PDMS- and poly(tert-butyldimethylsilyl methacrylate) (PMASi)-enriched phases, respectively. Contact angle measurements revealed the influence of the copolymer composition on their surface free energy, with block copolymers exhibiting surface free energies as low as 15.0 mJ m(-2). A laboratory assay using 96-well plates was used to assess the activity of the block copolymers against two marine bacteria (Pseudoalteromonas sp. and Shewanella sp.) isolated from the Mediterranean Sea. Coatings based on PDMS-based block copolymers demonstrated anti-adhesive performances against the two strains better than that of the coating containing only PMASi-based polymers. Coatings based on diblock copolymers demonstrated antifouling performances in the field that were better than those of the corresponding coatings containing triblock copolymers. Results of both lab and field assays showed that the antifouling properties were related to coatings possessing the highest receding water contact angle.