Effects of hydrolyzable comonomer and cross-linking on anti-biofouling terpolymer coatings

Antifouling coatings based on the cross-linked terpolymer chains made of methyl methacrylate (MMA), the hydrolyzable tributylsilyl methacrylate (TBSM) or triisopropylsilyl methacrylate (TIPSM) and acrylic acid (AA) were developed. By varying the hydrolyzable monomer content and the cross-linking degree, a set of such prepared coatings were evaluated in terms of their degradation rate, swelling degree, contact angle and antifouling properties. After immersed in seawater, such coatings quickly self-generate a thin and swollen hydrogel layer at the water-contacting surface due to the hydrolysis of the hydrolyzable groups on the surface. Further hydrolysis leads to a gradual degradation and self-peeling of this hydrogel layer. Their antifouling properties were evaluated by both the adsorption of fluorescence-labeled bovine serum albumin and the field-testing in a real marine environment. Our results reveal that it is such a layer-by-layer hydrogel formation and self-peeling process that leads to an excellent antifouling property. Therefore, it is vitally important to delicately balance the hydrogel formation and the self-peeling rate to achieve the best antifouling of such a coating by carefully choosing a proper cross-linking degree and a suitable content and type of the hydrolyzable comonomer.