Jet Plasma Gas-liquid Interaction And Its Modification On The Surface Of Carbon Fibers

Atmospheric pressure low-temperature plasma interaction with liquids is currently a popular topic of research in the field of plasma,which has a wide range of applications in bioengineering,food processing,and surface modification of materials.Plasma discharge generates a large amount of oxygen-containing active substances,electrons,ultraviolet radiation,charged particles,etc.Therefore,when plasma interacts with a liquid(deionized water),chemicals in the gas phase such as oxygen-containing radicals and nitrogen-containing radicals dissolve into the liquid and generate corresponding oxygen-containing radicals and ions inside the liquid,prompting the transformation of deionized water into plasma-activated water.However,there is a lack of research work on the mechanism of plasma-liquid interaction,the measurement of internal components of activated water,and whether activated water can be combined with conductive material surface treatment.To address these issues,this paper investigates the plasma gas-liquid interaction and its application in carbon fiber surface treatment using an atmospheric pressure plasma jet discharge device built by independent design,as follows:First,by changing the width of the grounding electrode and the concentration of argon/oxygen mixture,the influences on the jet length and discharge intensity were explored respectively.The results show that when the width of the grounding electrode is 1.5cm,the intensity of the OH radical in the gas phase is 2.3 times that of the argon discharge alone when the oxygen content is 0.5%and the jet is 3 mm away from the nozzle.Secondly,the mechanism of jet plasma gas-liquid phase interface action was explored.The results show that when the plasma jet acts on the liquid surface,the jet rate and the solution conductivity are the main parameters leading to the bending of the gas-liquid phase interface.The geometric data of the gas-liquid phase interface are extracted and sampled using image processing methods,and then the geometric curves of the gas-liquid phase interface are fitted using analytical function methods and machine learning methods.It provides a new method for more in-depth study of the mechanism of the gas-liquid interface and quantitative experimental data processing.Thirdly,the change of components in the solution was measured.The experimental results showed that the solution H2O2 and OH concentrations of the cascade discharge plasma action are higher than those of the pulsed discharge;the H2O2 and OH concentrations of the argon-oxygen mixed discharge are higher than those of the argon discharge;the NO3-and NO2-concentrations of the cascade discharge are smaller than those of the pulsed discharge;the concentration of NO3in the argon-oxygen mixed discharge is higher than that of the argon discharge.The changes of the internal components of the solution are positively correlated with the intensity of the gas phase spectrum.The addition of metal ions accelerates the Fenton reaction in the solution,which is helpful to increase the concentration of oxygen-containing active ions in the plasma activated water.Finally,the surface of carbon fiber activated by gas phase pulse discharge plasma,cascade discharge plasma and corresponding plasma was compared.It was found that the contact Angle of carbon fiber with argon/oxygen mixed cascade discharge plasma activated by water treatment for 600 s was reduced from 80.12° to 56.04°.The interlaminar shear performance of the composite can be improved by 19.5%.In summary,this paper investigated the atmospheric pressure plasma jet,the gas-liquid reaction mechanism,the change of active particles inside the solution and the treatment of carbon fiber modification.The layer-by-layer series of studies provide a new approach to regulate and optimize the application of atmospheric pressure plasmaliquid interaction in material surface treatment.