In situ erosion study of Kapton using novel hyperthermal oxygen atom source

A novel hyperthermal oxygen atom source has been used to perform in situ erosion of Kapton surfaces at room temperature, and these surfaces have been examined using X-ray photoelectron spectroscopy before and after exposure to different fluences of oxygen atoms, and then after exposure to air. The data indicate that the initial attack site is the carbonyl portion of the Kapton by reaction with atomic oxygen to form carbon dioxide, which desorbs. The oxygen-to-carbon-atom ratio decreases from 0.23 to 0.11 during a 24-h exposure to a hyperthermal oxygen-atom flux of about 1.4 x 10 exp 14 atoms/sq cm per sec. Following the 24-h oxygen-atom exposure, the sample was exposed to air for 3 h. The O, N, and C concentrations return to values similar to those obtained before the oxygen-atom exposure due to reaction with molecular oxygen in the air. Previous data from space and ground simulations indicate an increase in the surface oxygen content with exposure to atomic oxygen and then air before analysis. The results obtained demonstrate that it is necessary to examine the chemical effects of oxygen-atom degradation of Kapton without air exposure before surface characterization. (Author)