Chemical alteration of poly(vinyl fluoride) Tedlar® induced by exposure to vacuum ultraviolet radiation
| Autor: | Michael L. Everett, Gar B. Hoflund |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Analytical chemistry
General Physics and Astronomy chemistry.chemical_element Surfaces and Interfaces General Chemistry Radiation Condensed Matter Physics Oxygen Surfaces Coatings and Films Amorphous solid chemistry.chemical_compound chemistry X-ray photoelectron spectroscopy Chemisorption Atom Layer (electronics) Vinyl fluoride |
| Zdroj: | Applied Surface Science. 252:3789-3798 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2005.05.061 |
| Popis: | In this study the chemical alteration of poly(vinyl fluoride) Tedlar® by vacuum ultraviolet radiation (VUV) (115–400 nm) has been examined using X-ray photoelectron spectroscopy (XPS). The initial F/C atom ratio of 0.34 decreases to 0.17 after a 2-h exposure. The F/C atom ratio is further reduced to a steady-state value of approximately 0.04 after a 24-h exposure. Similarly, the O/C atom ratio is reduced from 0.08 to 0.05 and then to 0.02 during these two exposures. As the F and O are removed by VUV exposure, the C concentration increases from 70.5 to 82.0 and then to 94.6 at.% thus forming a graphitic or amorphous carbon-like layer which erodes more slowly than the virgin Tedlar surface. Exposure of the VUV-damaged surface to O2 results in chemisorption of O, indicating that reactive sites are formed during the chemical erosion by VUV. Further exposure to VUV removes this chemisorbed oxygen but a subsequent exposure to air at atmospheric conditions causes a three-fold increase in O chemisorbed at the surface. Comparison of XPS data indicates that the mechanisms of chemical alteration by VUV radiation and hyperthermal (∼5 eV) atomic oxygen (AO) are similar. |
| Databáze: | OpenAIRE |
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