Fabrication Of Low Surface Energy Antifouling Coatings Based On Polyurethane And Application In Marine Anti-Fouling

Marine Biofouling refers to the biofouling layer formed by the adhesion and growth of marine microorganisms,animals,and plants on the surface of ships or other offshore marine equipment.Marine biological fouling brings about many effects,including but not limited to:accelerating the corrosion of ships and offshore equipment,forming ship fouling,and resulting in the decline of ship speed.Marine anti-fouling materials-related technologies have become one of many bottlenecks restricting the development of China’s marine economy,the reliability of coastal defense security,and future deep-sea exploration.Organotin antifouling coatings have been banned due to ecological impacts,and the development of environmentally friendly long-term low surface energy marine antifouling materials is an important direction in the future.Firstly,7-amino-4-methylcoumarin was introduced into the silicon-containing polyurethane by chemical covalent bonding which was prepared by condensation polymerization of polytetrahydrofuran ether glycol,polydimethylsiloxane,and isocyanate diisocyanate condensation.Polyurethane resin can be self-crosslinked at room temperature,and the coating realized the coordination of multiple anti-fouling mechanisms of fluorescent antifouling,contact bacteriostasis,and fouling desorption,to solve the static antifouling requirements of marine equipment in the ocean.The water contact angles were more than 105°,with properties of low surface energy(21.0-22.0 mN/m)and low elastic modulus(1.5-2.2 MPa),which endowed fouling release performance.The coating containing 7-amino-4-methyl coumarin has a good UV fluorescence response,the excited fluorescence can influence the settlement of the diatom,and 7-amino-4-methyl coumarin has the potential to inhibit microbial growth.When the coumarin content was only 1.307 wt ‰,the bactericidal rate against bacteria E.coli was 98.17%and maintained the antifouling performance for 120 days.To hydrophilically modify the silicon-containing polyurethane to achieve the anti-protein adhesion effect of the coating,a monofunctional hydrophilic segment P VP-OH was prepared.The PVP-OH terminal group has reactivity with isocyanate groups and is then introduced into the silicon-containing polyurethane through covalent bonds to form a low surface energy marine antifouling coating with a hydrophilic surface.Tests had shown that the introduction of hydrophilic segments PVP-OH improved the hydrophilicity of the coating,strengthened the anti-protein performance of the coating,and reduced the elastic modulus(<1.1 MPa)of the coating.Compared with non-hydrophilic coatings,the average diatom coverage of PVP-10-SiPU decreased from 7.3%(PVP-0-SiPU)to 2.6%,and the algae coverage decreased by more than half,and the coating exhibited excellent marine antifouling performance within 90 days.