Preparation Of Polyacrylate Nanocomposite Antibacterial Coatings Through Polymerizable Emulsifier/Ionic Ligand

The introduction of nanoparticles into polymers,such as silver(Ag NPs)and titanium dioxide(TiO₂ NPs)to prepare polymer nanocomposite antibacterial coatings has attracted much attention.However,agglomeration problems of nanoparticles greatly limit their performance and applications.Therefore,how to effectively achieve the uniform dispersion of nanoparticles in the polymer matrix is still an urgent problem to be solved.Due to the special surface properties,the surface of different nanoparticles can exhibit a positive or negative potential in aqueous medium.Based on this,it is a promising method to design suitable cationic or anionic ligands and achieve uniform dispersion of nanoparticles by electrostatic interaction.In this thesis,a cationic ligand,vinylbenzyldimethyldodecylammonium chloride(VDAC)and an anionic ligand,sodium mono dodecyl maleate(SMDM),were synthesized.TiO₂ NPs and Ag NPs were selected,which they show negative and positive potential in aqueous medium,and VDAC and SMDM interact with TiO₂ NPs and Ag NPs to control their dispersion,respectively.Besides,VDAC and SMDM were also used as polymerizable emulsifiers,copolymerized with the main comonomers methyl methacrylate(MMA)and butyl acrylate(BA),and polyacrylate/TiO₂ and polyacrylate/Ag nanocomposite antibacterial coatings were prepared by emulsion polymerization.The structures and performances of VDAC and SMDM,polymer nanocomposite emulsions and coatings were characterized by nuclear magnetic resonance(¹H-NMR),fourier transform infrared spectroscopy(FTIR),dynamic light scattering(DLS),zeta potential,transmission electron microscopy(TEM),X-ray diffraction(XRD),scanning electron microscopy(SEM),atomic force microscopy(AFM)and water contact angle(WCA).In addition,a systematic study on the antibacterial properties of nanocomposite coatings was carried out by various methods.The results show that VDAC and SMDM were successfully synthesized.As cationic/anionic ligand,VDAC and SMDM can effectively attenuate the agglomeration of TiO₂ NPs and Ag NPs in water and achieve preliminary uniform dispersion,which their particle sizes decrease from 426.8±15.4 nm and 241.7±41.5nm to 127.4±13.4 nm and 15.8±1.3 nm,respectively.As polymerizable emulsifier,VDAC and SMDM are both excellent emulsifiers compared to traditional emulsifier sodium dodecyl sulfate(SDS),and can be copolymerized with MMA and BA.Through the action of VDAC and SMDM,particle sizes of TiO₂ NPs and Ag NPs in the polymer matrix decrease to about 5 nm after emulsion polymerization.The antibacterial tests show that the polyacrylate/TiO₂ and polyacrylate/Ag nanocomposite coatings prepared by VDAC and SMDM have excellent antibacterial properties.In addition,the coatings also have a long-term and stable antibacterial effect,and maintain nearly 100%inhibition rate in 7 days and almost completely inhibit the biofilm formation,showing excellent anti-biofoiling performance.The nanocomposite coatings prepared in this thesis are expected to be applied in various fields where antibacterial properties are highly demanded,effectively protecting the performance of industrial products as well as human health.