Influence of atomic oxygen exposure on surface resistivity of silicon doped polyimide affecting spacecraft charging

• We report the cause of resistivity change of polyimide containing silicon affecting spacecraft charging.
• The AO-exposure changed the surface morphology of polyimide and caused loss of certain amount of thickness.
• The concentration of oxygen increases and the concentration of carbon decreases due to AO-exposure.

In the present research work, the vulnerability of silicon doped polyimide by atomic oxygen present in LEO (lower earth orbit) of space was investigated. AO-exposure of a fluence of 5.4 × 1018 atoms cm−2 significantly changed the surface resistivity properties of polyimide which is a prime factor governing spacecraft surface charging problem. This amount of fluence affected surface morphology and eroded the surface thickness as observed by SEM (scanning electron microscopy), laser beam imaging and surface profilometer study. This much exposure also increased the oxygen and silicon content on the surface as observed by XPS (X-ray photoelectron spectroscopy) and EDX (Energy-dispersive X-ray spectroscopy) study.