High Fluence Ion Beam Modification of Polymer Surfaces: EPR and XPS Study

Polyethylene, polyamide-6 and polyimide foils implanted with 100 keV and Sb+ ions to a fluence range of 10e15-10e17 cm-2 have been studied using the electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) methods. The experimental data allow the comparison of the implantation-induced changes both in a given polymer foil under different ion beam regimes and in different polymers under similar ion-bombardment conditions. The high fluence implantation of boron ions, depositing energy mainly via electronic stopping, was found to be accompanied with the effective formation of π-bonded carbon-rich clusters. By contrast, heavier (phosphorus and antimony) ions, which deposit energy predominantly in nuclear collisions, produced a lower concentration of π-radicals and a less carbonised top surface layer. The peculiarities and main trends of the alterations of the polymer structure and composition induced via electronic and nuclear stopping have also been discussed.