Preparation Of Zwitterionic Polymer By Atom Transfer Radical Polymerization And The Study Of Its Antifouling Properties

Marine biofouling harm to ships tremendously and most antifouling coatings contain toxic antifouling agents.The release and accumulation of these toxic substances will do great harm to the ecological environment and their use is also increasingly limited.Environmental-friendly fouling release coatings(FRCs),which based on PDMS(polydimethylsiloxane),have already been commercialized and have good development prospects.However,it was found that the antifouling performance of FRCs is not very well when the ship is not navigating and the mechanical strength of the PDMS are relatively low.In this paper,the surface and substrate of PDMS were modified with zwitterionic polymers with great anti-protein adsorption properties,and the effects of zwitterionic polymer modification on the antifouling performance properties were studied.Zwitterionic polymer was grafted on the surface of nano-silica by atom transfer radical polymerization and the modified nano-silica were introduced on the surface of silicone rubber.The method of directly introducing zwitterionic polymer grafted nanoparticles and the method of grafting polymer brushes after introducing the initiator immobilized nano-silica were investigated.The morphologies prepared by two different fabrication process and the effect of polymers with different functional groups on the antifouling performance of the material surface were studied.The diatoms adhesion density on the polymer modified surface made by zwitterionic,anionic and nonionic monomers were compared.It was found that the number of diatoms attached to the zwitterionic polymer modified surface reduced 97.6% than unmodified silicone rubber,which had the best antifouling performance.And the anion polymer modified surface reduced 96.1%.However,the antifouling properties of non-ionic polymer attached surface did not be improved.In order to improve the antifouling performance and mechanical strength of PDMS substrate at the same time,a block polymerization of zwitterionic monomer containing acrylate structure and aminopropyl-terminated PDMS was carried out in this paper to prepare ABA type block polymer(SBMA-b-PDMS-b-SBMA)which possess polyacrylic acid and polydimethylsiloxane component in molecular chain.The block polymer film was hydrophobic by testing contact angle.The Zeta potential of block polymer decreased by increasing p H,but it was closer to electrical neutrality than unmodified PDMS.The tensile strength of block polymer was 20 MPa,which was much higher than silicone coating or resin.The results of diatom anti-adhesion experiments showed that the number of diatoms adhered on the surface of SBMA-b-PDMS–b-SBMA polymer film reduced by 19-41.5% compared to silicone rubber,and the antifouling performance and mechanical strength were simultaneously improved.Interaction energies including Van der Waals interaction energy,electric double layer interaction energy,and polar interaction energy between the diatoms and the antifouling materials were calculated by XDLVO theory.The relationship of the interaction energies and the distance between diatoms and material were also studied.The results showed that the polar interaction was the most important factor affecting the diatoms adhesion and the antifouling performance is enhanced by increasing the interaction energy.