Contact Properties and Surface Structure of Polypyromellitimide Films Modified by Direct-Current Discharge

The contact properties, chemical structure, and surface morphology of polypyromellitimide films modified at the cathode and anode by dc discharge have been investigated. A significant improvement in wettability and an increase in the work of adhesion, total surface energy, and its polar component, which persist for a long time when the films are stored in air under ambient conditions, are shown. The change in the chemical structure of the plasma-modified films has been studied using X-ray photoelectron spectroscopy, and the formation of oxygen- and nitrogen-containing groups on the surface has been revealed. Examination of the films by atomic force microscopy indicates a change in the surface morphology and an increase in its roughness. Modification of films by plasma leads to a significant improvement in their adhesion properties.