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

The curve‐fitting of the complex C 1s 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 O 1s intensity and that predicted from the intensities of the high‐binding‐energy C 1s 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.