Vapor-based Fabrication Of Multifunctional Antibacterial Coating And Their Properties

The accumulation of bacteria on the surface of medical devices and equipment is a widespread problem.Antibacterial coatings that prevent bacterial infection and reduce bacterial toxic pollution have attracted great attention in recent decades.Traditional fabrication of antibacterial coatings rely on solution-based methods,and the resultant coatings are usually mono-functional.However,limitations of solution-based fabrication schemes,as well as the short-lasting antibacterial effect and poor biocompatibility of the mono-functional antibacterial coatings can no longer fulfill the requirement of modern biomedical needs.In this work,multifunctional antibacterial coatings,including hydrophilic biocompatible antibacterial coating,hydrophobic antibacterial coating for biomedical fabrics,and replenish antibacterial coating with biodegradable layer,were prepared using initiating chemical vapor deposition(iCVD)method.The details research results are as follows:1.Using dimethylaminomethylstyrene(DMAMS)as antibacterial moity,vinyl pyrrolidone(VP)as hydrophilic moiety,and ethylene glycol acrylate(EGDA)as crosslinking agent,functionally graded polymer coatings with P(DMAMS-co-EGDA)as bottom layer and P(DMAMS-co-VP-co-EGDA)as surface layer were obtained using iCVD.Gram-negative Escherichia coli(E.coli)and Gram-positive Bacillus subtilis(B.subtilis)were selected as model bacteria for antibacterial tests.Antibacterial test results revealed that the bactericidal effect of the sample with the P(VP-co-EGDA)layer is still as high as 99%,while the contact angle decreased from 60° to 29°,which was attributed to the introduction of a large number of hydrophilic functional groups on the surface.The introduction of the hydrophilic surface component also induced a hydration layer on the surface upon immersion in the bacterial solution,which improved the bacterial antifouling rate from 20% to more than 85%.The cytotoxicity test showed that the hydrophilic antibacterial coating is more cell-friendly than the single-layer P(DMAMS-co-EGDA)antibacterial coating.This research has practical significance for the surface modification of medical devices and implants that are susceptible to bacterial contamination.2.Employing perfluorodecyl acrylate(PFDA)and DMAMS as monomers,hydrophobic antibacterial coatings were obtained on fabric surface using iCVD.DMAMS served as the antibacterial agent which enhanced the antibacterial properties of the fabric,while PFDA served as the low surface energy substance which enhanced surface hydrophobicity.Optimized antibacterial and hydrophobic performance was obtained by adjusting the ratio of these two monomers during the deposition process.Scanning electron microscope(SEM)observation shows a uniform polymer coating on the fiber surface.The obtained hydrophobic antibacterial fabrics showed antibacterial rate as high as 99%.The coated fabric maintained good hydrophobicity after 100 cycles of friction under the pressure of 3.15 k Pa and rigorous washing at 200 rpm/min in water.Therefore,the iCVD modified fabric not only maintained its original characteristics but also obtained hydrophobic and antibacterial properties.3.In order to avoid the formation of biofilm induced by prolonged bacteria exposure,a sandwich-structured replenishing antibacterial coating was prepared using iCVD.A biodegradable layer,including poly(methacrylic anhydride)(PMAH),poly(methacrylic anhydride-co-methacrylic acid)(P(MAH-co-MAA)),and poly(methacrylic anhydride-coethylene glycol diacrylate)(P(MAH-co-EGDA)),was added in between two layers of bactericidal P(DMAMS-co-EGDA).In order to meet different application scenarios,degradation time was adjusted by tuning the thickness and composition of the intermediate degradable layer.In PBS buffer(p H = 7.4),the degradation time of 800 nm PMAH,P(MAHco-MAA),and P(MAH-co-EGDA)coatings was 4 h,30 min,and 72 h,respectively.The sandwich-structured coatings with the three intermediate layer showed similar degradation time of the top two layers.All sandwich-structured coatings showed 99% bactericidal rate before degradation,and more than 95% bactericidal rate after replenishment.The self-replenishing antibacterial coatings are thus expected to have broad applications in different biomedical scenarios.Using iCVD as the main research method,this thesis improved the single-functional antibacterial material through above three works,and have obtained multi-functional antibacterial coatings with different functions and application scenarios.This work is thus expected to shed light on the development of multifunctional antibacterial coatings.