低温等离子体处理及丙烯酸接枝改性膨化聚四氟乙烯薄膜

采用He等离子体对膨化聚四氟乙烯(ePTFE)薄膜进行表面亲水处理,并引发接枝丙烯酸单体实现持久亲水改性.实验探究了不同等离子处理工艺和接枝工艺对ePTFE薄膜亲水性能的影响,并利用接触角、X光电子能谱(XPS)进行表征.研究结果表明,等离子体预处理后,ePTFE薄膜表面的接触角由145°降至102°;再接枝丙烯酸单体...

Surface modification of low temperature plasma-pretreated ePTFE film by AAc graft copolymerization

PTFE adheres poorly to other materials due to its low surface energy and chemical inertness, which leads to failure of PTFE in many industrial applications.To spread the applications, numerous methods for surface modification have been developed to activate the PTFE surface for improving its wettability and adhesion ability.This study focused on the surface modification of expanded poly(tetrafluoroethylene）(ePTFE）film by a two-step process based on low-pressure plasma treatment followed by acrylic acid （AAc）graft copolymerization.The influences of different plasma treatments and graft copolymerization conditions on the hydrophilicity of film surface were studied.The wettability of the ePTFE film surface was determined by water contact angle, and the surface elemental compositions and the type of functional groups on the surface of the treated ePTFE samples were evaluated by X-ray photoelectron spectroscopy (XPS).The results indicated that the contact angle of ePTFE film declined from 145° to 102° when it was only treated by plasma treatment.After AAc grafted copolymerization, the contact angle decreased further to a smaller value.And the wettability of the film was improved obviously and kept constant.The condition of plasma treatment was He, 100 W, 90 s.The condition of AAc graft copolymerization was 30%(vol.), 70℃,3 h.XPS analysis showed that the element ratio of F/C declined from 1.960 to 0.853, while the element ratio of O/C rose from 0 to 0.147.The result indicated that plasma treatment could greatly change the surface chemistry as well as morphology of ePTFE films.The surface roughness increased with plasma treatment time.From XPS measurements, it could be seen that the polar hydrophilic groups had been successfully grafted onto the ePTFE surface.The inert fluorine elements were partly replaced by oxygen polar groups, which was the fundamental reason for the improvement of hydrophilicity of ePTFE film.