Processes Induced in DLC/Polyimide Structures by Irradiation with 60Co γ-Rays

Abstract

The DLC/Kapton structures irradiated with 60Co γ-rays at doses to 1 MGy have been studied by measuring transmission and attenuated total reflection (ATR) spectra. It has been shown that there are significant changes in the spectra in the ranges of vibrations of О–Н, CH2, and CH3 bonds due to radiation-induced processes in the byproducts of polyimide synthesis and residual solvents. Significant differences were found in the radiation-induced processes occurring in the bulk and near-surface region of a polyimide film and DLC/polyimide structures. After irradiation, the bulk of polyimide exhibited bands due to asymmetric and symmetric vibrations of the CH3 group. Bands associated with the vibrations of the CH2 group were additionally observed in the near-surface region. The formation of CH2 groups in the near-surface layer under irradiation was more pronounced in DLC/polyimide structures than in polyimide films; this was due to the additional supply of hydrogen from the DLC film.