Crosslinked polydimethylsiloxane exposed to oxygen plasma studied by neutron reflectometry and other surface specific techniques

被引:436
作者
Hillborg, H
Ankner, JF
Gedde, UW [1 ]
Smith, GD
Yasuda, HK
Wikström, K
机构
[1] Royal Inst Technol, Dept Polymer Technol, SE-10044 Stockholm, Sweden
[2] ABB Corp Res, Dept High Voltage Engn, SE-72178 Vasteras, Sweden
[3] Univ Missouri, Reactor Res Facil, Columbia, MO 65211 USA
[4] Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA
[5] Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA
[6] Univ Missouri, Ctr Surface Sci & Plasma Technol, Columbia, MO 65211 USA
[7] Univ Missouri, Dept Chem Engn, Columbia, MO 65211 USA
关键词
oxygen plasma; polydimethylsiloxane; surface properties;
D O I
10.1016/S0032-3861(00)00039-2
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Spin-coated specimens of crosslinked polydimethylsiloxane (PDMS) exposed to radio-frequency (RF) and microwave (MW) oxygen plasma were studied by specular neutron reflectometry, X-ray photoelectron spectroscopy (XPS), Wilhelmy balance, contact angle measurements, scanning electron microscopy and atomic force microscopy. Neutron reflectometry and XPS showed that the oxygen plasma led to the formation of a smooth (<10 nm), oxidised surface layer with a thickness of 130-160 nm. The oxidised layer contained a mixture of the original polymer and silicon bonded to three or four oxygen atoms (SiOx). The oxidised layer was thinner after longer plasma exposure, indicating a decrease in specific volume due to a conversion of the polymer structure to an inorganic SiOx-rich structure. The formation of the SiOx-containing layer with low segmental mobility was further confirmed by the small hysteresis in the Wilhelmy balance measurements. The similarity in the hydrophobicity recovery kinetics of specimens aged in dry air, dry argon and vacuum and XPS data showed that the hydrophobicity recovery is not due to contamination through adsorption from the atmosphere but due to migration of low molar mass PDMS species to the surface. Scanning electron microscopy also showed the presence of surface cracks in heavily oxidised specimens. (C) 2000 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:6851 / 6863
页数:13
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