X-ray photoelectron spectroscopy studies of the stability of Al/Mg/PET interfaces

The interfacial chemistry of an Al/Mg/PET sample, prepared by thermally eva porating first Mg and then Al on to a polyethyleneterephthalate (PET) film, was studied by X-ray photoelectron spectroscopy (XPS). The Mg/PET system s howed two types of Mg species, namely an O-Mg-C complex, from reaction with the carbonyl group on PET, and metal-like clusters. The deposition of Al r esults in intermetallic mixing, which is manifested by alloy formation and Mg enrichment at the surface. It appears that some Al atoms penetrate the M g region to react with carbonyl groups in the PET and form an interfacial c omplex with O-Al-C bonding. The stability of this sample was studied on exp osing it to air and then rinsing it with water. The metal overlayers are st rongly modified by these treatments, although the bonding at the PET interf ace appears relatively unchanged.