A Study Of Cationic Polyelectrolyte Anti-fouling Coating With Functional Transformation Mechanism

In recent years,due to the fouling of biofouling on the surface of the hull,the navigation speed of ships slows down and fuel costs increase year by year,causing serious losses to marine economy.Hydrolyzable cationic polyelectrolytes have been widely used as a cationic bactericide which can be hydrolyzed to zwitterionic polyelectrolytes with anti-adsorption ability.However,due to the structure of its organic internal salt,it can't be mixed with the hydrophobic base.In this paper,amphiphilic block copolymers were prepared,which were self-assembled in organic solvent to form nanoparticles with cationic polyelectrolyte as core and hydrophobic segment as shell solving the problem of phase separation of cationic polyelectrolyte in the matrix.The critical conditions for nanoparticle reversion and the antifouling properties of the coatings were also investigated.Firstly,by the method of atom transfer radical polymerization(ATRP),amphiphilic block copolymer was prepared by continuous feeding with DMAEMA as a hydrophilic monomer and isooctyl methacrylate(EHMA),lauryl methacrylate(LMA)and hexadecyl methacrylate(HMA)as hydrophobic monomers,respectively.The structure and molecular weight were characterized by NMR(1H NMR)and gel permeation chromatography(GPC).In a chloroform solution,amphiphilic block copolymers were reacted with methyl chloroacetate or ethyl chloroacetate to prepare a series of nanoparticles with hydrophobic segments as the shell and P(DMAEMA-CH2COOCH3)(PCBMAM)or P(DMAEMA-CH2COOCH2CH3)(PCBMAE)as the core.Water contact angle and 1H NMR tests showed that the critical mole ratio of hydrophilic segment and hydrophobic segment of PEHMAx-b-PCBMAMy,PLMAx-b-PCBMAMy and PHMAx-b-PCBMAMy were both y/x?0.75.The critical mole ratio of hydrophilic segment and hydrophobic segment PEHMAx-b-PCBMAEy,PLMAx-b-PCBMAEy and PHMAx-b-PCBMAEy were respectively y/x?0.75,y/x?0.5 and y/x?0.75.Nanoparticle reversion is affected by the length and the glass transition temperature of the hydrophobic segments.The shorter the hydrophobic segments and the lower the glass transition temperature of the hydrophobic segments,the easier the nanoparticles reversion.The nanoparticles are blended into the substrate to prepare antifouling coatings.The antifouling test indicates that the nanoparticles have the sterilization performance,and the ability of the coated anti-bovine serum protein(BSA)and staphylococcus aureus is gradually enhanced with the increase of the incorporation of nanoparticles.In summary,this paper achieved the goal of preparing cationic bactericidal and antibacterial functional conversion nanoparticles.At the same time,this paper adopts ATRP bulk polymerization method to achieve the goal of quantitative preparation of diblock copolymers and improve the atomic economic efficiency,so the results of this study are very practical for industrial production.