Characterisation of PEEK, PET and PI implanted with 80 keV Fe+ ions to high fluencies

Polyimide (PI), polyetheretherketone (PEEK) and polyethylene terephthalate (PET) foils were implanted with 80 keV Fe+ ions at room temperature at fluencies of 0.2 × 1016 cm−2– 5.0 × 1016 cm−2. The implanted polymers were subsequently annealed at 200 °C for 20 min. The depth profiles of implanted Fe atoms and compositional changes of the implanted polymers were characterised by RBS and ERDA methods. A significant shift of the Fe concentration maximum to the sample surface with increasing ion fluence was observed and annealing does not influence the Fe profiles. The implanted Fe profiles cannot be reproduced by SRIM and TRIDYN simulations. Hydrogen desorption from the surface layer of all polymers is observed, the effect being the most pronounced on PET. Desorption of oxygen from the samples implanted to lower fluences is observed too. On the samples implanted to the highest fluence of 5.0 × 1016 cm−2, however, oxygen concentration increases to the value close to that of pristine polymer, this phenomenon is strongly pronounced after the annealing, which is provided in the ambient atmosphere. The electrical, optical and structural properties of the implanted polymers were investigated by sheet resistance measurement and UV–Vis spectroscopy. With increasing ion fluence, the sheet resistance decreases, but a saturation effect is achieved at a fluence of 5.0 × 1016 cm−2. UV–Vis absorbance increases simultaneously with the decline of the optical band gap Eg. After annealing, no significant changes in UV–Vis spectra or in electrical properties were observed.