X-ray photoelectron spectroscopy studies of the evaporated aluminum/corona-treated polyethylene terephthalate interface

X-ray photoelectron spectroscopy (XPS) has been used to investigate the interface between in situ thermally evaporated aluminum (Al) and corona-treated polyethylene terephthalate (PET). Thickness effects were eliminated by using normalized concentrations. It is found that Al bonds to both CO and C–O groups by forming a cyclic AlOC complex. Within this complex, Al is bonded to both C and O, as indicated by the appearance of low binding energy (BE) peaks in both the C(1s) and the O(1s) spectra. The aromatic rings also react with Al and lose their aromaticity; an average of one carbon per ring ultimately reacts to form carbide-like bonds.