Plasma Surface Modification and Characterization of POSS-Based Nanocomposite Polymeric Thin Films
详细信息 查看全文
- 作者：Brian H. Augustine ; Wm. Christopher Hughes ; Kathryn J. Zimmermann ; Ashley J. Figueiredo ; Xiaowen Guo ; Charles C. Chusuei ; Jessica S. Maidment
- 刊名：Langmuir
- 出版年：2007
- 出版时间：April 10, 2007
- 年：2007
- 卷：23
- 期：8
- 页码：4346 - 4350
- 全文大小：177K
- 年卷期：v.23,no.8(April 10, 2007)
- ISSN：1520-5827
文摘
The effect of a remote oxygen plasma on nanocomposite hybrid polymer thin films of poly[(propylmethacryl-heptaisobutyl-polyhedral oligomeric silsequioxane)-co-(methylmethacrylate)] (POSS-MA) has been examined byadvancing contact angle, X-ray photoelectron spectroscopy (XPS), and variable-angle spectroscopic ellipsometry(VASE). Exposure to a 25 W remote oxygen-containing plasma was found to convert the surface of POSS-MA filmsfrom hydrophobic to hydrophilic within 20 s. The exposure time needed for this conversion to occur decreased asthe O2/N2 ratio in the plasma environment increased, indicating a positive correlation between the hydrophilicity andthe presence of oxygen in the plasma. Local bonding information inferred from high-resolution XPS data showed thatthe isobutyl bonding to the POSS moiety is replaced with oxygen as a result of plasma exposure. Finally, VASE datademonstrates that increasing the weight percent of POSS in the copolymer significantly impedes the oxygen plasmadegradation of POSS-MA films. On the basis of these results, a model is presented in which the oxygen plasma removesisobutyl groups from the POSS cages and leaves a SiO2-like surface that is correspondingly more hydrophilic thanthe surface of the untreated samples and is more resistant to oxidation by the plasma. The ability to modify surfacesin this manner may impact the utility of this material for biomedical applications such as microfluidic devices in whichthe ability to control surface chemistry is critical.