Preparation And Performance Study Of Zwitterion-based Synergistic Marine Antifouling Coating

Marine biofouling has been a long-term problem faced by the development of the marine industry.Ships,wharves and other shells below the waterline are in contact with seawater for a long time,and the adhesion of marine organisms can lead to a decrease in ship speed and faster corrosion of the hull,and also affect the normal operation of underwater facilities,causing serious economic losses.By applying antifouling coating,the formation of biofouling can be effectively delayed or inhibited,and it has become the most widely accepted and effective method due to its simple process and wide applicability.Traditional antifouling coatings are mainly used to prevent marine fouling by gradually exuding antifouling agents(toxic materials)from the coating,but this method also causes secondary pollution to the marine environment while inhibiting the adhesion of marine organisms.Therefore,the development of efficient and long-lasting environmentally friendly marine antifouling coatings has become a hot spot for research and considerable progress has been made,but single-function antifouling coatings have always been difficult to meet the stringent requirements of complex marine environments and long-term service time.In view of this,we compound various factors that can affect the normal rhythm of marine organisms,such as fluorescence and electrochemistry,with polymeric antifouling coatings,and substantially improves the antifouling effect through the synergy of multiple functions and confers them long-term durability under harsh application environments.The specific studies are as follows:(1)A fluorescent hydrophilic antifouling coating inspired by the lubricious epidermal and luminescent properties of Watasenia scintillans was prepared,achieving excellent performance through the synergistic effect of a highly hydrophilic surface and a luminescent layer.The pentaerythritol triacrylate embedded in the acrylic resin matrix was used as the active site to ensure the grafting density of poly(sulfobetaine methacrylate)on the coating surface.The results of the antifouling test showed that the coating could effectively resist the adhesion of non-specific proteins,and the adsorption density of bovine serum albumin decreased from 220.83 ng/cm~2 in the blank control to40.01 ng/cm~2.The adhesion density of diatom was reduced from 383 n/mm~2 in the blank control to 67 n/mm~2.Since long-lasting light can effectively interfere with the normal biological rhythm of fouling organisms,the attachment of diatom was further reduced to 4 n/mm~2 after laminating fluorescent particles with PSBMA coating.The results of long-term panel tests underwater also demonstrated the effectiveness of the coating in complex aquatic environments.(2)A hydrophilic antifouling coating with high strength was prepared by combining the zwitterionic polymer poly(acrylic acid-sulfobetaine)(P(AA-SBMA))with inorganic particles calcium sulfoaluminate(C4A6S).The dense hydrated layer formed by P(AA-SBMA)conferred long-term underwater antifouling ability to the coating surface,the adsorption density of non-specific proteins decreased from 176μg/cm~2 to 19μg/cm~2,and the adhesion density of diatoms decreased from 549 n/mm~2to 54 n/mm~2.Through the reaction of amino and carboxyl groups,the copolymer was firmly bonded to the substrate through the deposition of dopamine,which significantly improved the adhesion strength of the coating,and the adhesion energy density on the various substrates surface was up to 381 J/m~2.Meanwhile,the nanocrystals generated by C4A6S greatly enhanced the hardness of the composite coating,reaching a strength comparable to that of ceramic materials with 4H.(3)A self-healing antifouling coating with excellent mechanical strength was prepared by a simple“one-step”method.A specific structure of amphiphilic block copolymer polydimethylsiloxane-poly(2-(dimethylamino)ethyl methacrylate)(PDMS-PDMAEMA)was introduced into the self-healing polydimethylsiloxane-based polyurethane(PDMS-PU)system,and the PDMAEMA chain segments were zwitterionized into the structure of poly(sulfobetaine)(PSBMA)during the PU molding process.The PDMS segments in the amphiphilic polymer and polyurethane are intertwined to form a semi-interpenetrating network,and PSBMA segments migrate outward when submerged underwater,resulting in an antifouling coating with a microphase-separated structure.The adsorption density of non-specific proteins on the coating surface decreased from 156μg/cm~2 to 14μg/cm~2,and the adhesion density of diatoms decreased from 425 n/mm~2 to 18 n/mm~2.In addition,the organically modified montmorillonite(MMT)effectively improved the mechanical properties of the coating through ligand bonding,and the composite coating showed a significant increase in fracture strength compared to PU.The long-term durability and excellent antifouling performance of the coating in complex real-world aquatic environments were also demonstrated by the results of long-term underwater pegboard tests.(4)A self-driven composite antifouling coating was successfully prepared by combining a water-driven triboelectric nanogenerator(TENG)with antifouling coating.The solution etching method was used to generate nanocrystals,and the resulting micro-nano-scale roughness was used to prepare a superhydrophobic surface.Or superhydrophobic surfaces are prepared using simple nanoparticles compounded with self-healing polyurethane.The low-frequency and low-intensity alternating electric field formed around the electrode by the contact separation of TENG and water waves effectively destroys the stable double-charge layer on the surface of PU-Si coating,inhibits the formation of bio-conditioned film at the early stage of biofouling formation,reduces the adhesion of subsequent fouling organisms,and avoids subsequent pollution formation.A series of antifouling experiments in laboratory and real environments demonstrated that the water-wave-driven anti-biofouling coating exhibited excellent surface protection performance,with the adsorption density of non-specific proteins on the coating surface decreasing from 521μg/cm~2 to 19μg/cm~2,and the adhesion density of diatoms decreasing from 561 n/mm~2 to 21 n/mm~2.The water wave impact experiment within a month on the coating revealed no significant degradation in electrochemical output performance and antifouling performance,indicating the long-term durable performance of the composite coating in the underwater environment.