Wettability of ultraviolet excimer-exposed PE, PI and PTFE films determined by the contact angle measurements
Wettability of ultraviolet excimer-exposed PE, PI and PTFE films determined by the contact angle measurements
复制标题
DOI：
10.1016/s0927-7757(03)00263-2
复制
发表时间：
2003-08-29
影响因子：
5.2
通讯作者：
Tagawa, M
中科院分区：
文献类型：
--
作者：
Gotoh, K;Nakata, Y;Tagawa, M
通过接触角测量和X射线光电子能谱（XPS）研究了紫外（UV）准分子光照射对聚合物薄膜物理化学表面性质的影响。在环境空气中，将波长为172nm的紫外光照射到聚乙烯（PE）、聚酰亚胺（PI）和聚四氟乙烯（PTFE）薄膜上。采用静滴法和Wilhelmy法测定了未照射和紫外照射薄膜上的水的前进接触角和后退接触角，以此作为润湿性的衡量指标。对于PE和PI薄膜，经过几秒或几十秒的紫外照射，水接触角显著降低。XPS数据表明，这种润湿性的增加归因于薄膜表面原子氧浓度的增加。PTFE薄膜的润湿性由于紫外照射没有改变。当紫外照射过的PE和PI薄膜在环境空气中储存时，在几天的时间尺度上观察到水接触角增加，即疏水恢复。研究表明，低分子量氧化物质的气化以及氧化表层中聚合物链的重新取向和迁移是空气中疏水恢复的原因。还尝试对覆盖有金属网的PI薄膜进行紫外照射，以制备具有未照射和紫外照射表面区域的薄膜。通过Wilhelmy法在恒定界面移动速度下连续记录重量，观察到两个区域之间前进接触角和后退接触角的差异。Wilhelmy法与紫外光刻技术相结合，能够同时评估处理过和未处理表面的润湿性。（C）2003 Elsevier B.V.保留所有权利。
Effects of the exposure of ultraviolet (UV) excimer light on the physicochemical surface properties of polymer films were investigated by contact angle measurements and X-ray photoelectron spectroscopy (XPS). The UV light at wavelength of 172 nm was exposed to polyethylene (PE), polyimide (PI), and polytetrafluoroethylene (PTFE) films in ambient air. The advancing and receding contact angles of water on the unexposed and UV-exposed films were determined by the sessile drop and the Wilhelmy methods as a measure of the wettability. For the PE and PI films, remarkable decrease in the water contact angle was accomplished by the UV exposure of several or several 10 s. The XPS data showed that such increase in the wettability was attributed to the increased atomic oxygen concentration at the film surfaces. The wettability of the PTFE film did not change due to the UV exposure. When the UV-exposed PE and PI films were stored in ambient air, the increase in the water contact angle, i.e. the hydrophobic recovery, was observed over a time scale of several days. It was suggested that the gasification of the low-molecular weight oxidized materials as well as the reorientation and the migration of polymer chains in the oxidized surface layer was responsible for the hydrophobic recovery in air. The UV exposure was also attempted to the PI film being covered with a metal mesh to prepare the film having both non-exposed and UV-exposed surface regions. The differences in the advancing and receding contact angles between the both regions were observed on the continuous weight recording at constant interfacial moving velocity by the Wilhelmy method. The Wilhelmy method in combination with the UV lithography technique enabled the simultaneous evaluation of the wettabilities of the treated and untreated surfaces. (C) 2003 Elsevier B.V. All rights reserved.