Compositional alteration of polyimide under high fluence implantation by Co+ and Fe+ ions

Polyimide (PI) foils were implanted with 40 keV Fe+ and Co+ ions to the fluences of 2.5 × 1016–1.25 × 1017 cm−2 at the ion current densities of 4, 8 and 12 μA cm−2. Surface morphology and compositional alteration of the implanted polymer have been studied using atomic force microscopy, transmission electron microscopy, Rutherford backscattering and X-ray photoelectron spectroscopy. Carbonisation of the surface layer, followed by oxygen and nitrogen depletion is observed. These processes reach the saturation level at the applied high fluences. A further increase of ion fluence and density of ion current does not change the composition; only an increase in the metal concentration is observed. It is shown that metal ion implantation to high fluence at high ion current density can be effectively employed to form metal/polymer nanocomposites with required parameters.