PMMA SURFACE MODIFICATION UNDER KEV AND MEV ION-BOMBARDMENT IN RELATION TO MAMMALIAN-CELL ADHESION

Spin casted poly methyl methacrylate (PMMA) films were submitted to Ga + (15 keV), Xe+ (4 keV) and He+ (1 MeV) ion bombardments with fluences varying between 10(+12) and 10(+16) ions/cm(2). The surface modificat ions were studied by time-of-flight secondary ion mass spectrometry (T oF-SIMS) and X-ray photoelectron spectroscopy (XPS). The evolution of ToF-SIMS peaks characteristic of the polymer and of the degradation we re followed as a function of the ion fluence. Surface deoxygenation an d loss of the methacrylate pendent group were observed. These results are discussed regarding the kind of energy deposition mode (electronic and nuclear). The XPS results confirmed the surface deoxygenation. Fi nally, the influence of the ion beam modifications on the adhesion of mammalian cells were investigated. For this purpose, the samples were reconditioned by a solution containing both a protein and a surfactant prior to inoculation with human epithelial cells in a serum free nutr itive medium. The results showed a preferential cell adhesion in the b ombarded areas.