以1 W功率的Ar等离子体对聚丙烯(PP)多孔膜作了表面处理,通过失量法和扫描电镜(SEM)法研究了等离子体的气氛压力和处理时间的表面刻蚀作用,并以水通量法评价了PP膜多孔隙内部的改性状况。结果表明,表面刻蚀作用随着等离子体气氛压力的降低及处理时间的延长而增强。中等气氛压力(18 Pa或30 Pa)的等离子体处理可使PP膜均匀通水,表明具有适中能量水平以及活性粒子密度的等离子体气氛是实现多孔膜多孔隙内部均匀改性的重要因素。为实现PP膜多孔隙内部的均匀处理同时降低表面刻蚀作用,10min、18Pa的等离子体处理条件较为合适。处理表面产生的羧基改善了表面亲水性,但表面接触角在5 d内由44.2°急剧上升到了66.0°,之后1 a内变化平稳。
The surface treatment of porous polypropylene membrane was carried out by Ar plasma with a low power of 1 W.After the detailed investigation of surface etch effects by the plasma atmosphere pressure and the plasma time based on the weight-loss measurement and SEM observation,the surface modification of pore walls into the porous membrane was evaluated based on the water flux method.More surface etches occurred by plasma treatments with lower atmosphere pressures and longer plasma times,and thorough surface modification on the pore walls of the porous membrane was achieved by plasma treatments with the medium atmosphere pressure of 18 Pa or 30 Pa,when the plasma time was enough(10 min).It is obvious that the active species with enough energy level and specie amount in the plasma atmosphere would be responsible for the thorough surface treatment throughout the membrane pores.In the end,an optimal plasma condition with the atmosphere pressure at 18 Pa and the plasma time of 10 min was determined,when only a slight surface etch was induced.A hydrophilic surface with a contact angle of 44.2°has been reached when some polar carboxyl groups was produced on the surface by plasma treatment.However,the surface contact angle would increase sharply to 66.0°in 5 d,subsequently become relatively steady in 1 a.