Synthesis And Properties Of Hydrophobic Antibacterial Coatings

Pathogenic bacteria are everywhere,and when they are on public facilities and some medical devices,they can have a serious impact on human health.In order to solve the problem of bacterial adhesion,many antibacterial materials have been developed,among which coating is the most convenient and efficient way.Low surface energy materials have received widespread attention because they can reduce the degree of bacterial adhesion,and have good aging resistance.The use of them with synthetic organic antibacterial agents can synergistically enhance the surface antibacterial ability.This article uses 4,5-dichloro-2-n-octyl-4-isothiazolin3-one(DCO)and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride(QAC)as organic antibacterial agents.Construct additive antibacterial materials and structural antibacterial materials are successfully prepared hydrophobic antibacterial low surface energy coatings,which improved its antibacterial ability.The main research results are as follow:(1)Using hydroxyl terminated polydimethylsiloxane(SiOH2),tetraethyl silicate(TEOS),n-octyltriethoxysilane(C2)as reactants to prepare silicon-containing low surface energy matrix resin.Different amounts of DCO were added to characterize and analyze the surface wettability,light transmittance,antibacterial properties,and surface roughness.The results showed that as the amount of DCO increased,the growth inhibition of the coating on Escherichia coli and Staphylococcus aureus also increased.When the DCO content was 4.0wt%,the inhibition rate of Staphylococcus aureus reached 99.7%,and the inhibition of E.coli reaches to 99.9%.The addition of DCO did not reduce the hydrophobicity(103-108°)of the coating,and the surface energy was kept at a low level(21-23 mJ/m2).The morphology of the coating was observed with a 3D profiler.At the same time,the surface roughness Ra of the coating with DCO added was below 0.65?m,which was not much different from that without DCO.In the visible light range,the coating has good light transmittance,and is a colorless transparent coating,with water absorption below 0.6%,and no swelling of the coating will occur.(2)Adding(QAC)into the silicon-containing low surface energy matrix resin participates in the process of forming a cross-linking network,anchoring the antimicrobial agent in the structure.It will not be released into the environment,which can improve the antibacterial longterm effect of the coating.X-ray photoelectron spectroscopy test results show that the distribution of QAC content on the surface of the coating is higher than the distribution inside the coating,and the bacteria and the coating only contact the surface.Therefore,the high distribution of QAC on the surface is more beneficial to achieve the antibacterial effect.The adhesion experiments to Escherichia coli and Staphylococcus aureus have also been verified.When the QAC content is 10.0wt%,the antibacterial rate of the two bacteria is as high as 99.9%.While introducing the organic antibacterial agent containing quaternary ammonium salt,the contact angle characterization shows that the hydrophobicity(104-110°)and low surface energy(21-23mJ/m2)characteristics of the surface have not changed.Nearly 100%transmittance in the visible light band indicates that it has good light transmittance and is a transparent colorless coating.The water absorption rate will increase with the increase of QAC content,but it remains at a low level without swelling.The coating morphology was observed with a 3D profiler,and the surface roughness Ra of the QAC-containing coatings was all below 0.75?m,which was not much different from the samples without QAC.(3)Trimethyloxyphenylsilane(Ph),TEOS,C2,octyltrimethoxysilane(C1),QAC was used as reactant to prepare antibacterial coating,and its surface wettability and antibacterial properties were characterized and analyzed.The addition of Ph in different content does not affect the hydrophobicity of the coating.The water contact angle is about 103°.The pencil hardness of the coating without Ph is B.When the Ph content is about 20wt%,the pencil hardness of the coating can reach 2H.In addition to improve its mechanical properties,and the presence of QAC makes the coating still have good antibacterial properties against E.coli and Staphylococcus aureus.