Generation And Application Of Surface Glow Plasma Based On Micro-discharge

Low temperature plasmas generated by glow discharge have many advantages,such as good discharge uniformity,abundant active particles,moderate power density,etc.,so it has great application value in the fields of material surface modification,film deposition,air purification,etc.However,it is difficult to form glow discharge directly in atmospheric air,which seriously limits the industrial application of glow plasmas.In this dissertation,the concept of micro discharge is introduced creatively.A method of forming large area surface glow discharge plasmas in atmospheric air is proposed by means of the construction of a strong non-uniform electric field and the provision of additional initial electrons and by means of surface dielectric barrier.A variety of micron electrode structures have been formed,and a variety of forms of large-area atmospheric air surface glow discharge plasmas have been produced.The possibility of these structures and the generated plasmas applied in high efficiency and industrialization potential for polymers and high-performance material surface functionalization is analyzed.The material surface modification platform of glow discharge plasma was built.The effects of electric field,electrode parameters,treatment methods,etc.on discharge and material treatment are discussed.Firstly,the control strategy of surface glow plasma generation based on micro discharge is developed.Through simulation analysis and experimental research,the comparison between the surface micro discharge electrode structure and the traditional macro electrode structure is made.The effects of electrode structures of different scales on electric field distribution,initial electron supply and discharge path length are studied.The theoretical characteristics of surface micro-discharge electrode structure which is conducive to atmospheric air surface glow discharge are obtained.Specifically,the distribution of the unidirectional non-uniform electric field intensity along the electric field lines is conducive to the control of the density of electron avalanches.At the same time,the open structure of the electrode causes the diffusion of the inner electrons to the outer open space,which is conducive to the priority of the inner electrons to provide seed electrons for the outer space,so as to enhance the diffusivity of the discharge.In addition,the field emission in the strong electric field under the microelectrode structure can first provide the initial electrons far higher than the traditional macroelectrode structure for the discharge space,which is conducive to the realization of macro-discharge under the condition of low voltage.Secondly,two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer.The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation.In particular,the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased,and the treated objects can be prevented from ion pollution caused by the electrode in the discharge.It has broad application prospects in the fields of aerodynamics and material surface treatment.Afterwards,a method of forming large-area glow discharge plasmas with good diffusivity in atmospheric air based on the composite network-surface laminated electrode structure with multiple potentials is proposed.This method can enhance the intensity of the space electric field and generate glow discharge plasma under the condition that voltage is lower than 1k V.Through the alternating electric field,the charged particles diffuse from the surface of the electrode to the space to enhance the treatment of aramid fabric.According to the changes of surface morphology,contact angle and surface energy of aramid fabric,it can be seen that the surface roughness and surface energy of the material treated by plasma are significantly improved.After 30s of treatment,the contact angle decreases by 83.85~o and the surface energy increases 3.4times.This method has the advantages of low discharge voltage,good discharge uniformity,good material treatment effect,and so forth.It has good application prospects for the industrialization of aramid fabric surface modification with high efficiency.Finally,on the basis of an ultrathin wire contact electrode structure,a nonuniform electric field is designed to realize diffuse discharge in atmospheric air.A method of high efficiency treatment of carbon fiber fabrics by glow discharge plasmas at low discharge voltage is proposed.Through this method,the carbon fiber fabrics are directly used as a part of the electrode,and a strong electric field area is formed on the surface of the carbon fiber fabrics,so that the plasmas are directly generated on the surface of the carbon fiber fabrics.The high active plasmas generated in this study can not only introduce nitrogen functional groups that are difficult to be introduced by traditional air plasma treatment methods and a large number of oxygen functional groups on the surface of carbon fiber fabrics but also improve the surface roughness and wettability of the material.In addition,the important effects of surface electric field intensity and plasma treatment time on the modification effect were investigated.It lays a good technical foundation for the industrial application of carbon fiber surface modification with high efficiency and continuity in atmospheric air.