Preparation And Application Of Antibacterial Coatings By RATRP

With the development of new technology and pollution of the environment,more and more people began to pay attention to the surrounding atmosphere and their own health.In the daily life,we have to be surrounded by the coating on the wall,and if these coatings are polluted by the bacteria or microorganism then we will be affected by the bacteria or microorganism.As a result,we might be ill at different degrees.Put the fact into consideration,paying more attention to the research on the antimicrobial coating is becoming more and more important.Thus,it is urgent to produce antimicrobial coatings with practical function and promising commercial value.Polyurethane(PU)coatings are common in coatings market.They are mostly used on wood surface,automobile surface,paper surface,leather surface or surfaces which need to be protected from mildewing or microorganism.These coatings are often used in the field of automobile,aviation,marine,architecture,plastics,electromechanics,petrochemics and so on.This kind of coatings have promising market use and commercial benefit with the advantages of high adhesive force,low film-forming temperature,high rigidity,weather resistance,abrasive resistance,good chemical resistance.Sulfobetain zwitterionic compounds are materials with the structure of sulfobetain groups and zwitterionic groups or mixture with cation/anion end groups.Due to its special structure,this kind of material has quite good antimicrobial and hydrophilic qualities.These antimicrobial agents with low molecule weights are normally able to kill microorganism quickly with stable antimicrobial quality and good color stability.However the disadvantages of weak chemical stability,drug resistance after use,poisonous decomposition can't be ignored.When we connect the antimicrobial groups to the macromolecule backbones we will get macromolecule antimicrobial materials with improving antimicrobial quality,Sulfobetain zwitterionic macromolecule materials have been widely used in the field of water treatment,health care,food and packaging materials.Reverse atom transfer radical polymerization is a living polymerization method which is widely used and rapidly developed in recent years.This method keeps the advantages and avoids the disadvantages of Atom transfer radical polymerization method.Via reverse atom transfer radical polymerization we can use common initiator and catalyst to controllably structure functional macromolecule chains with certain length and density on the surface of materials.In normal process of reverse atom transfer radical polymerization,CuCl2 and Bpy usually act as catalyst and initiator which cause disadvantages of high cost of raw materials,poisonousness and low grafting density.As far as we are concerned about all above facts,the polymerization system which was introduced by early research group in our laboratory was used.This system was used to produce antimicrobial polyurethane(PU)coating via RATRP method.The concrete research steps are in the following.Firstly,the sulfobetain zwitterionic monomer(DMCHPS)was synthesized via one step method using dimethylaminoethyl methacrylate(DM)and sodium 3-chloro-2-hydroxy propanesulphonate(CHPS)as raw materials.Then the structure and purity of DMCHPS were characterized by fouriter transform infrared spectra(FTIR),nuclear magnetic resonance(1H NMR),element analysis(EA),X-ray photoelectron spectroscopy measurement(XPS).Wettability,antimicrobial quality and cototoxicity(MTT)were characterized by X-ray photoelectron spectroscopy measurement(XPS),water contact angle measurement(SCA),antibacterial performance analysis and vitro cytotoxicity test,respectively.The results of these tests showed that:the monomer DMCHPS was successfully synthesized and the compound has good hydrophilic quality,antimicrobial quality and certain cytotoxic.Secondly,3-chloro propyl trimethoxysilane(CPTM)was adopted to serve as a coupling agent as well as a ligand which was introduced in early research work.The new system of CPTM/CuCl2 was used to polymerize polyurethane coating which was named as PU-Si-g-P(DMCHPS).Surface structure,wettability,of the PU coatings before and after modification were characterized by fourier transform infrared spectra(FTIR),X-ray photoelectron spectroscopy measurement(XPS),water contact angle measurement(SCA),respectively.The results showed that zwitterionic brushes were successfully fabricated on the PU surfaces,and the content of the grafted layer increased gradually with the polymerization time.The antimicrobial quality of the PU coatings was evaluated by antibacterial performance analysis.The results showed that the PU coatings have a good inhibitory effect on E.coli and S.aureus.The antifouling quality of the PU coatings was evaluated by protein adsorption tests in vitro.It was found that all the PU coatings showed improved resistance to nonspecific protein adsorption.Vitro cytotoxicity showed that these coatings were no cytotoxic according to the grading standards of cytoxicity.Lastly,low grafting density is a disadvantage both in RATRP and ATRP.In this work,the surfaces of polyurethane were treated by LaCl3·6H2O to obtain modified surfaces with hydrated layers.The reaction of surface-initiated RATRP was carried out easily,which may be attributed to the enriched hydroxyl groups on the hydrated layers.An innovation found in this work is that some free lanthanum ions(La3+)reacted with CPTM and the product served as mixed ligand complex.The mixed ligand complex instead of conventional 2,2'-bipyridine was adopted to serve as a ligand in the process of RATRP.As a result,PU coatings grafted with well-defined polymer brushes P(DMCHPS)were obtained.PU coatingss before and after modification were characterized by FTIR,XPS,SEM,SCA,respectively.The results showed that zwitterionic brushes P(DMCHPS)were successfully fabricated on the PU surfaces,and the content of the grafted layer(O/C ratio)increased gradually with polymerization time increased.The antimicrobial quality of the PU coatings was evaluated by antibacterial performance analysis.The results showed that the PU coatings have a certain inhibitory effect on E.coli and S.aureus.The antifouling quality of the PU coatings was evaluated by protein adsorption tests in vitro.It was found that all the PU coatings showed improved resistance to nonspecific protein adsorption.Vitro cytotoxicity showed that some coatings were no cytotoxic according to the grading standards of cytoxicity while some are cytotoxic which it conformed to the Hormesis of rare earth.