Hydrophobic recovery of UV/ozone treated poly(dimethylsiloxane):: adhesion studies by contact mechanics and mechanism of surface modification
Hydrophobic recovery of UV/ozone treated poly(dimethylsiloxane):: adhesion studies by contact mechanics and mechanism of surface modification
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DOI：
10.1016/j.apsusc.2004.06.005
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发表时间：
2005-01-31
影响因子：
6.7
通讯作者：
Vancso, GJ
中科院分区：
文献类型：
--
作者：
Ol치h, A;Hillborg, H;Vancso, GJ
以聚二甲基硅氧烷(PDMS)为基料的硅橡胶(Sylgard 184和170)在紫外光和臭氧的联合作用下进行了表面处理。使用不同的标准表面表征技术，如水接触角测量、XPS和原子力显微镜(AFM)，分析了处理效果与停止处理后经过的时间的函数关系。然而，这项研究的主要焦点是应用Johnson-Kendall-Roberts(JKR)接触力学方法来研究紫外线/臭氧表面处理前后的PDMS样品。随着紫外线/臭氧曝光量的增加，薄膜表面逐渐形成了一层亲水性的、类似二氧化硅的表面层，并随着模数的增加而增加。通过增加接触角，观察到紫外线/臭氧暴露后随后的疏水性恢复。这支持了这样的假设，即疏水恢复主要是由于游离硅氧烷逐渐覆盖永久的硅胶结构和/或极性基团的重新定向造成的。含有均匀分散的填料(Sylgard 184)的PDMS在氧化表面区坍塌成光滑的SiOx层(最终表面粗糙度)时，表面粗糙度(通过AFM)降低
Silicone elastomers (Sylgard 184 and 170), based on poly(dimethylsiloxane) (PDMS), were surface treated by a combined exposure to UV and ozone. The effects of the treatments were analyzed as a function of time elapsed after stopping the treatments using different standard surface characterization techniques, such as water contact angle measurements, XPS and atomic force microscopy (AFM). However, the primary focus of this study was to apply the Johnson-Kendall-Roberts (JKR) contact mechanics approach to investigate PDMS samples prior to and following UV/ozone surface treatment. A gradual formation of a hydrophilic, silica-like surface layer with increasing modulus was observed with increasing UV/ozone exposure. A subsequent hydrophobic recovery after UV/ozone exposure was observed, as indicated by increasing contact angles. This supports the hypothesis that the hydrophobic recovery is mainly caused by the gradual coverage of a permanent silica-like structure with free siloxanes and/or reorientation of polar groups. PDMS containing a homogenously dispersed filler (Sylgard 184), exhibited a decreasing surface roughness (by AFM) when the oxidized surface region "collapsed" into a smooth SiOx layer (final surface roughness