Siloxy Silylester Methacrylate Diblock Copolymer-Based Coatings with Tunable Erosion and Marine Antifouling Properties

pMATM2-b-p(MMA-co-BMA) diblock copolymers composed of a block of poly[bis(trimethylsiloxy)methylsilyl methacrylate] (MATM2) and a second block of a random copolymer of methyl methacrylate (MMA) and n-butyl methacrylate (BMA) were synthesized by the reversible addition–fragmentation transfer process with controlled molar masses and low molar mass dispersities. Paints were formulated using these diblock copolymers as binders, without any biocides, or associated with low amounts of biocidal compounds such as dicopper oxide (Cu2O), 4,5-dichloro-2-n-octyl-4-isothiazole-3-one (DCOIT), and 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile. All the coatings exhibited a hydrophobic surface at the initial stage with an evolving surface chemistry when immersed in artificial seawater. The erosion of the coatings was shown to be driven by the molar proportion of MATM2 units in the diblock copolymer. The antifouling properties were evaluated by in situ static immersion in the Mediterranean Sea. Cu2O (20 wt %)–DCOIT (2 wt %)-based coatings with 30 mol % of MATM2 in the seawater-hydrolyzable binder exhibited similar antifouling performances to a commercially available self-polishing coating over 16 months of field immersion. Contact angles and mass loss measurements, as well as scanning electron microscopy observations enabled the investigation of the parameters influencing the antifouling activity of the coatings.