Chemical alteration of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen

In this study the erosion of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen (AO) has been examined using X-ray photoelectron spectroscopy (XPS). Initially the Tedlar film had F/C and O/C atom ratios of 0.45 and 0.11, which decrease to 0.018 and 0.04, respectively, after a 2-h exposure to a flux of 2 × 1015 atoms/cm2 s AO with an average kinetic energy of 5 eV. This exposure essentially produced a graphitic or amorphous carbon-like layer with a carbon content greater than 90 at.%. Longer AO exposures do not alter the composition of this layer significantly. Exposure to O2 or air nearly doubles the oxygen content in the near-surface region. This is due to dissociative oxygen adsorption at reactive sites formed at the polymer surface during AO exposure. Further exposure to AO removes this chemisorbed oxygen.