’’Hot’’ atom interactions with polymer surfaces

Abstract

Sputter deposition of metal films is being used more widely in the industrial sector for the coating of many materials. In an effort to identify interface chemical bonds, if any, the interactions of sputter‐deposited (’’hot’’) Ni atoms with polyvinyl alcohol (PVA), polyvinyl methyl ether (PVME), polymethyl methacrylate (PMMA), and polyvinyl acetate (PVAC) surfaces have been investigated using x‐ray photoemission spectroscopy (XPS). Nickel atoms and ions resulting from the bombardment of clean Ni foil by 1000‐eV argon ions were impinged normally on clean polymer surfaces. At Ni coverages of about one third monolayer or more on both PVA and PVME, a new peak in the oxygen 1s core level spectrum was observed which had a binding energy 1.7 eV smaller than the original bulk polymer oxygen. The resulting Ni complex can be contrasted to that formed when thermally evaporated Ni atoms interact with the same surface. In the latter, a Ni–O–C chelate complex was formed having a new oxygen 1s binding energy 1.3 eV smaller than the bulk. This difference implies that the hot or sputter‐deposited Ni atoms are more strongly bound to the oxygen than they are in the chelate complexes produced by thermally evaporated Ni. The interactions of the hot Ni atoms with the more complex PMMA and PVAC are more difficult to interpret. On these polymer surfaces, XPS cannot distinguish between metal complexes formed by evaporation and those complexes formed by sputtering.