【作者】 王娟；

【导师】 丁可； 郭颖；

【作者基本信息】 东华大学 ， 物理学， 2025， 硕士

【摘要】 低温大气压等离子体与液体的相互作用在生物工程、食品加工和材料表面改性等领域具有广泛的应用前景。在等离子体放电过程中,会产生大量的含氧活性物质、电子、紫外辐射和带电粒子。当等离子体与液体接触时,气相中的化学物质会溶解到液体中,生成相应的自由基和离子,进而促使去离子水转变为等离子体活化水（PAW）。然而,等离子体与液面相互作用的机制及不同工艺参数对PAW活性影响的研究,尤其是对液相处理对聚对苯二甲酸乙二醇酯（PET）薄膜表面改性的影响,仍较为缺乏。本研究采用大气压等离子体射流放电设备,分析了等离子体气液相互作用的机制,并探讨其在PET薄膜表面处理中的应用。首先,研究了纳秒脉冲针-环电极大气压等离子体射流（APPJ）与气液界面相互作用产生的附加力及其对PAW性能的影响。通过电压-电流波形、射流长度、增强电荷耦合器件（ICCD）高速成像和电子密度测试等手段,分析了等离子体的物理特性,并比较了不同放电强度下气相活性粒子发射强度与气体温度的变化,同时利用比色法检测了PAW中过氧化氢（H?O?）、亚硝酸根离子（NO₂^-）和硝酸根离子（NO₃^-）等活性物质的浓度。结果表明,等离子体射流与液面相互作用的附加力来源于高速运动的等离子体"子弹"对液面的冲击,推动了气液等离子体通道的形成。半经验公式分析显示,该力与等离子体子弹的能量密切相关,且受放电强度影响。研究还发现,放电强度通过影响作用力、气相组分和温度等参数,调控PAW中活性物质的溶解平衡及活性粒子浓度,其中电压调节效果优于频率。此外,本研究还分析了多种工艺参数（如接地电极与管口距离、脉冲放电参数、气体流量等）对等离子体射流、气相活性粒子浓度及液相活性粒子浓度的影响规律。通过PET薄膜表面性能的表征,发现液相等离子体处理在提高薄膜亲水性方面优于气相处理,尤其是碱性水浸泡后的效果最佳。结合时效性测试,液相处理（特别是碱性水处理）显著提高了薄膜的表面稳定性与粘附性。综上所述,本文研究了大气压等离子体射流的气液相互作用机制、工艺参数对PAW活性影响的规律,并探讨了其在PET薄膜表面改性中的应用,为大气压等离子体与液体相互作用在材料表面处理中的优化提供了新的思路。更多还原

【Abstract】 The interaction of low-temperature atmospheric pressure plasma with liquids has a wide range of applications in fields such as bioengineering,food processing,and surface modification of materials.During plasma discharge,a large amount of oxygen-containing active substances,electrons,ultraviolet radiation and charged particles are generated.When the plasma is in contact with the liquid,the chemicals in the gas phase dissolve into the liquid,generating the corresponding free radicals and ions,which in turn prompts the transformation of deionized water into plasma-activated water（PAW）.However,studies on the mechanism of plasma-liquid interaction and the effect of different process parameters on the activity of PAW,especially on the effect of liquid-phase treatment on the surface modification of polyethylene terephthalate（PET）films,are still relatively lacking.In this study,an atmospheric pressure plasma jet discharge device was used to analyze the mechanism of plasma gas-liquid interactions and to explore its application in the surface treatment of PET films.First,the additional force generated by the interaction of the nanosecond pulsed needle-ring electrode atmospheric pressure plasma jet（APPJ）with the gas-liquid interface and its effect on the performance of PAW were investigated.The physical properties of the plasma were analyzed by means of voltage-current waveforms,jet lengths,enhanced charge-coupled device（ICCD）high-speed imaging,and electron density tests,and the changes in the emission intensity of gas-phase active particles versus the gas temperature at different discharge intensities were compared,while the colorimetric method was used to detect hydrogen peroxide（H?O?）,nitrite ions（NO₂^-）and nitrate ion（NO₃^-）concentrations of reactive substances.The results show that the additional force of the plasma jet-liquid interaction originates from the impact of the high-speed moving plasma“bullets”on the liquid surface,which drives the formation of the gas-liquid plasma channel.Semi-empirical equations show that the force is closely related to the energy of the plasma bullets and is affected by the intensity of the discharge.It is also found that the discharge intensity regulates the dissolution equilibrium of active substances and the concentration of active particles in the PAW by affecting the parameters of force,gas-phase components and temperature,in which the voltage regulation is better than the frequency.In addition,this study also analyzes the influence laws of various process parameters（e.g.,the distance between the grounded electrode and the orifice,the pulse discharge parameters,the gas flow rate,etc.）on the plasma jet,the gas-phase active-particle concentration,and the liquid-phase active-particle concentration.Through the characterization of the surface properties of PET films,it was found that the liquid-phase plasma treatment was superior to the gas-phase treatment in improving the hydrophilicity of the films,especially the best effect after alkaline water immersion.Combined with the aging test,the liquid-phase treatment（especially the alkaline water treatment）significantly improved the surface stability and adhesion of the films.In summary,this paper investigates the gas-liquid interaction mechanism of atmospheric pressure plasma jet,the law of process parameters on the influence of PAW activity,and discusses its application in the surface modification of PET films,which provides a new idea for the optimization of atmospheric pressure plasma-liquid interactions in the surface treatment of materials.更多还原