XPS of chemically modified low-density polyethylene surfaces: observations on curve-fitting the C 1s spectrum

The curve-fitting of the complex C Is envelopes (obtained under high-energy-resolution XPS conditions) resulting, from the surface chemical modification of low-density polyethylene has been investigated. The main problem is modelling of the dominant, asymmetric component due to unmodified hydrocarbon. Two approaches have been compared, namely the use of a full (four-component) vibrational progression or a single peak with a lineshape recently introduced by Gelius. As well as goodness of fit criteria, the agreement between the measured 0 Is intensity and that predicted from the intensities of the high-binding-energy C Is components (from oxygen-containing functional groups) was used in the assessment. Under the relatively low-level, but practically relevant, modification conditions studied, the two approaches are equally effective. However, they can give rise to significant differences in the relative intensities of high-binding-energy components. Broadening of the various components as a function of treatment also has been studied. Copyright (C) 2002 John Wiley Sons, Ltd.