X-RAY PHOTOELECTRON-SPECTROSCOPY OF MODIFIED POLYMER SURFACES AND METAL POLYMER INTERFACES - CORRELATIONS WITH ADHESION

X-ray photoelectron spectroscopy (XPS) has been used to study the interfacial chemistry between evaporated Ag and polymer surfaces with and without plasma modification. The initial stages of metallization in the sub-atomic layer regime were monitored. For an oxygen-free polymer such as polyethylene (PE), which exhibits poor adhesion with evaporated Ag, the XPS results suggest no chemical interaction with the formation of very large Ag clusters. For an oxygen-containing polymer such as poly(ethylene terephthalate) (PET), where the adhesion of evaporated Ag is greater compared to PE, the XPS results suggest charge transfer between Ag and the carbonyl oxygen in PET. Plasma treatment with oxygen introduces specific reactive sites resulting in additional chemical bond formation between the evaporated Ag and the polymer surface. These results are consistent with the significant improvement in adhesion observed for plasma treatment with a reactive gas.