Abstract
The cause of the conspicuous Si content consistently observed on plasma polymers deposited on silicone rubber was investigated in this study. Plasma polymers of tetrafluoroethylene and of hexafluoroethane were deposited on the inside surface of Silastic tubings with and without oligomers by using a semicontinuous plasma polymerization reactor. This tube coating reactor is unique in the sense that the only surface which interacts with the plasma is the substrate surface (i.e., inside wall of tubing) and that plasma polymerization occurs in a very small volume of 3.3‐mm‐I.D. and 2‐cm‐long section of tubing at any given time. These two factors render the reactor a suitable system for the investigation of plasma‐substrate surface interaction. Silastic tubings free of oligomers were prepared by extracting the tubings as received with distilled n‐hexane for 3 h which yielded a 3% weight loss. It was found that the conspicuous Si content noted previously was not occasioned by the migration of oligomers through the plasma polymers but was caused by the redeposition of plasma copolymers formed from a mixture of the feed‐in monomer and the silicon‐containing volatile components evolved from the silicone rubber when exposed to the plasma. The presence of Si‐containing compounds in the plasma evidently interfered with the plasma polymerization of tetrafluoroethylene and hexafluoroethane. Without volatile oligomers (the extracted samples), ESCA analysis indicated that the plasma polymers contained large amounts of CF3, CF2, and CF moieties, just like most typical plasma polymers of these monomers deposited on nonreactive substrates. With the presence of volatile oligomers, the fluorine content decreased drastically, and a significant increase of oxygen‐containing and silicon‐containing moieties was observed. The influence of the volatile oligomers in the substrate on the balance between ablation and polymerization in plasma polymerization and its energy input level dependence (manifested by W/FM) were studied as well. The results were also discussed in relation to the bicyclic rapid step‐growth polymerization mechanism. Copyright © 1986 John Wiley & Sons, Inc.
Recommended Citation
Y. ‐. Yeh and H. Yasuda, "Plasma‐substrate Interaction: Effect Of Volatile Oligomers In Silicone Rubber On Plasma Polymerization Of Fluorine‐containing Monomers," Journal of Polymer Science Part A: Polymer Chemistry, vol. 24, no. 12, pp. 3233 - 3248, Wiley, Jan 1986.
The definitive version is available at https://doi.org/10.1002/pola.1986.080241208
Department(s)
Chemistry
Publication Status
Full Access
International Standard Serial Number (ISSN)
1099-0518; 0887-624X
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2023 Wiley, All rights reserved.
Publication Date
01 Jan 1986
