UV Photoemission Study of Defect States in Polyethylene Films

Abstract

ABSTRACTPhotoemission from evaporated Polyethylene films was measured in the spectral region between 6 and 11 eV. A significant increase in photoemission yield was observed after the films were exposed to O2 and to air containing ozone and ions from a diffuse glow discharge at reduced pressures. The enhancement can be attributed to oxygen and ozone reacting with the defects in the evaporated polyethylene films, which are unsaturated carbon double bonds in the polyethylene chain. For the ozonized polymer films deposited on gold substrates, the photoelectron spectra show a relatively high density of occupied states at 6.8 ± 0.3 eV below the vacuum level of the polymer and a photoemission threshold of 3.8 ± 0.3 eV. The implication of the results to contact charging of polyethylene is discussed.