INTERACTION OF LOW-ENERGY IONS (LESS-THAN-10 EV) WITH POLYMETHYLMETHACRYLATE DURING PLASMA TREATMENT

Using in-situ X-ray photoelectron spectroscopy (XPS) we investigated t he chemical modification of the polymethylmethacrylate (PMMA) surfaces after plasma and low-energy ion beam treatment. A comparison between plasma and ion beam treatment has shown, that for noble gases both tre atments produce absolutely the same modifications of the chemical comp osition on the PMMA surface. In reactive gases (O-2, N-2) molecular io ns were found to decompose polar bonds at the polymer surface, but the y do not contribute to the incorporation of reactive gas atoms. Reacti ve atomic ions and radicals are responsible for this incorporation. We found that in the case of PMMA less than three ions are needed to dec ompose the ester group (O-C=O) completely. Therefore, we conclude that the decomposition of the ester group by ions is a chemical and not a physical effect due to the kinetic energy of the ions.