Chemical alteration of poly(vinyl fluoride) Tedlar ® induced by exposure to vacuum ultraviolet radiation

• Published in: Applied surface science 2006-03, Vol.252 (10), p.3789-3798
• Main Authors: Everett, Michael L., Hoflund, Gar B.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fluoromers; Fluoropolymers; LEO; Low earth orbit; Physics; Tedlar; Teflon; Tefzel; VUV; XPS
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2005.05.061

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 O 2 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.