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研究了远程氧等离子体改性聚四氟乙烯(PTFE)的表面润湿性与表面结构的关系.用已知表面张力的液体测定接触角,采用Zisman曲线法求得试样的临界表面张力γC,利用扩展的Fowkes公式计算试样表面自由能γS及其分量γdS(色散力)、pγS(偶极矩力)和γhS(氢键力)的变化,并与远程氧等离子体中活性物种的分布进行相关性分析.结果表明:氧等离子体处理的PTFE表面润湿性是由表面自由能中极性分量(γpS+γhS),尤其是氢键力hSγ的大小决定的,而与表面能态没有特定关系;氧等离子体场中活性物种混合存在和较纯的高浓度自由基氛围均有利于极性分量(γpS+γhS)的增加,但表面自由能的变化则主要受电子、离子浓度的影响.X射线光电子能谱分析表明,经氧等离子体处理后,PTFE表面C—F键断裂形成的自由基与空气中的氧反应生成C—O和C=O活性基团,氧含量增大,使表面润湿性提高.
The relationship between the surface wettability and the surface structure of long-range oxygen plasma modified polytetrafluoroethylene (PTFE) was studied.The contact angle was measured by the liquid with known surface tension, and the critical surface tension γC of the sample was calculated by Zisman curve method , The extended Fowkes formula was used to calculate the change of free surface energy γS and its components γdS (dispersive force), pγS (dipole moment) and γhS (hydrogen bonding force), and the distribution of active species in remote oxygen plasma The results show that the wettability of PTFE treated by oxygen plasma is determined by the polar components (γpS + γhS), especially the hydrogen bonding force hSγ, but not with the surface energy states (ΓpS + γhS) increase, but the change of surface free energy is mainly affected by the concentration of electrons and ions. In the oxygen plasma field, the mixing of active species and pure high concentration of free radical atmosphere are conducive to the increase of polar components (γpS + γhS) The results of X-ray photoelectron spectroscopy showed that the radicals formed by the C-F bond cleavage on the surface of PTFE reacted with oxygen in air to form C-O and C = O active groups after oxygen plasma treatment, and the oxygen content increased. So that the surface wettability increased.