XPS investigations of two metal-PET interfaces formed by Zr and Al

X-ray photoelectron spectroscopy (XPS) was used to study two interfaces formed between polyethyleneterephthalate (PET) and thin layers of aluminum and zirconium deposited under ultrahigh vacuum conditions. The thicknesses of these layers were estimated to be about 10 and 4 Angstrom respectively. The interpretations were guided by difference spectra, especially for the Zr system, and it was concluded that different interactions operate at these two PET-metal interfaces. For the amounts deposited, Zr bonds especially to O atoms in PET, whereas Al beads to both C and O atoms; the latter metal shows both tending to carbonyl groups and direct Al-C bonding to the benzene-like rings. Comparisons were made for the behaviors of these systems on exposure to oxygen, and they were compared further with related systems.