RF-CF4 Plasma Treatment of Tetrafluoroethane Pre-deposited Paper, Part 1: Hypotheses on Surface Reactions

Abstract

CF₄ plasma treatment of a Teflon-like (1,1,1,2 tetrafluoroethane, TFE) chemical spray deposited on paper resulted in an increased level of elemental fluorine on the paper surface. However, TFE molecules undergo bond cleavage and ionization in the presence of the RF-CF₄ plasma environment. The abundant fluorine radicals grafted onto the paper surface, via the substitution and opening of the bonds in the cellulose polymers, yielded CF_x (x: 1–3) functionalities, as observed by XPS and ATR-FTIR analyses. Lower power (100 W) and treatment times (0.5 min) were sufficient to obtain very highly fluorinated surfaces. The change in the morphology of the surface by the exposure to plasma was complicated because the localized deposition and re-deposition of the plasma-generated molecules on the paper were superimposed on the surface reactions and degradation (etching) at the paper surface.

Keywords:

• Rf-plasma
• paper
• surface deposition
• fluorinated surface
• XPS
• ATR-FTIR

ACKNOWLEDGEMENTS

The author wishes to thank Professor Ferencz S. Denes and Dr. Sorin Manolache from the University of Wisconsin-Madison for the many useful discussions. I also thank to Emeritus Professor Raymond A. Young (University of Wisconsin-Madison) as major Professor and his valuable comments.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.