Study In Nanofibers Surface MgO Deposition And Antibacterial Properties By Pulsed Plasma

With the increasing improvement of people’s living standards,the demand for wearable antibacterial fabrics such as antibacterial masks and medical protective clothing is rising sharply.As one of the important production methods of antimicrobial fabrics,electrostatic spinning nanofibers show unique advantages in the field of wearable antimicrobial fabrics due to the advantages of small pore size,low grammage,good breathability and moisture permeability.In response to the demand for modification of low melting point nanofibers,a low-temperature pulse plasma modification method was established to realize the deposition of Mg O nanoparticles on the surface of low melting point polypropylene（PP）nanofibers.The prepared composite nanofibers showed good antibacterial properties.The specific studies are as follows.（1）A platform for dielectric blocking discharge（DBD）surface modification excited by a pulsed source was established to realize the surface modification of low melting point PP fibers.The applicability of the voltage/current integration method and the voltage/charge Lissajous method in calculating the power was investigated for the difficult problem of calculating the power of pulsed DBD discharge.The applicability of the above two methods under different conditions was different.When low voltage（<9 k V）was applied,the power values calculated by the two methods do not differ much from the measured power values.However,with applied high voltage（>9 k V）,the power values measured by the Lissajous method were closer to the power values measured by the standard method than those calculated by the voltage-current-integral method.So the Lissajous method is more suitable for power calculation at high voltage.This study provides a practical guide for power calculation of DBD systems driven by pulsed sources.（2）Parameter optimization and antibacterial performance study of self-cleaning composite nanofibers prepared by Ar/O₂ plasma.Ar/O₂ was used as working gasto investigate the performance of Mg O deposition under different pulse discharge parameters,including gas ratio,gas flow rate,plasma treatment time,contact time,etc.The influence of these parameters on fiber antibacterial performance was also studied.Under the optimal parameters:plasma discharge voltage of 4 k V,discharge frequency of 2 k Hz,pulse width of 50 ns,precursor concentration of 3 mol/L,Ar/O₂ ratio of 600/1,and treatment time of 5 min,and Mg O load of 2.140%,the bactericidal rate of the prepared composite nanofibers against E.coli was 95%after 7 h.（3）Preparation of self-cleaning composite nanofibers by air plasma and their antibacterial properties evaluation.Air was used as the reaction atmosphere to investigate the properties of deposited Mg O under various parameters,including plasma treatment time,contact time.Under the optimal treatment parameters:plasma discharge voltage of 13 k V,discharge frequency of 1 k Hz,pulse width of 50 ns,precursor concentration of 3 mol/L and treatment time of 2 min,and Mg O load was 2.250%,the anti-bactericidal rate against E.coli of composite fiber membrane achieved 100%after 7 h.