低频RF-等离子体处理对医用不锈钢表面润湿性能的影响

以聚乙烯-乙烯醇（EVAL）为模型高分子，研究了等离子体处理前后不锈钢表面EVAL溶液的铺展润湿情况、EVAL膜的形貌及其结合强度。并建立了医用不锈钢表面润湿性和表面自由能、表面结构之间的关系。研究结果表明：等离子体处理后，不锈钢表面的铺展润湿性显著提高。等离子体处理的最佳工艺条件为：氮气，偏压100V，时间10min。最佳条件处理后，不锈钢表面EVAL膜均匀性、致密度以及涂层与基体的结合强度均得到明显提高。反射红外（ATR—FTIR）、原子力显微镜（AFM）、X光电子能谱（XPS）分析结果显示Ar、N2气体等离子体，尤其是N2气体等离子体预处理后，材料的表面自由能（尤其是极性分量）显著增大，润湿性增强。极性分量的增加与等离子体时材料表面的清洗、刻蚀以及活性化有关。

Influence of RF-Plasma Pretreatment on Wettability of Medical Stainless Steel

Effects of low-frequency Ar,N_2 RF-plasma on wettability of medical stainless steel were studied in details. Wettability of EVAL solution, the morphology and bonding strength of EVAL coating on the stainless steel with and without plasma pretreatment were investigated. The correlation of surface wettability with surface free energy and surface structure was also established. Wettability was measured by contact angles of water droplet on the samples. Surface free energy (dispersive force and polar force) was calculated by contact angles of liquids whose surface tensions were known. Wettability of medical stainless steel after plasma pretreatment significantly increases and the optimum conditions of treatment are: N_2 gas plasma, bias voltage 100 V, time 10 min. Moreover, the uniformity, density and the bonding strength of EVAL coating on the stainless steel pretreated under the optimum condition are remarkably improved. Contact angle measurement results show that mainly because of the contribution of polar forces, the surface free energies of samples after plasma treatment are enhanced. ATR-FTIR, AFM, XPS results indicate that the modification of wettability and the increasing of surface free ~energy are due to surface cleaning, surface etching and surface activity.