| AVS 60th International Symposium and Exhibition | |
| Applied Surface Science | Monday Sessions |
| Session AS+BI-MoM |
| Session: | Organic Depth Profiling |
| Presenter: | A.E. Wright, Thermo Fisher Scientific, UK |
| Authors: | P. Mack, Thermo Fisher Scientific, UK A.E. Wright, Thermo Fisher Scientific, UK |
| Correspondent: | Click to Email |
Modern food packaging materials can be complex mixtures of polymers, with a wide range of surface properties, compositions and structures. X-ray Photoelectron Spectroscopy (XPS) is typically the technique of choice for analyzing polymeric surfaces, combining chemical selectivity and surface specificity. Core level XPS spectroscopy, however, is not always sensitive to compositional changes in complex mixtures of polymers. A commonly cited example of this would be in the analysis of blends of polypropylene and polyethylene. Each of the individual polymers in this case has an almost identical C1s spectrum, meaning the polymeric mixtures cannot be quantified using the core level data.
The valence region of the XPS spectrum, however, has been shown to be sensitive to compositional changes in polymeric mixtures even when the core level spectra are not. The XPS valence band of polyethylene and polypropylene, for example, are significantly different and using reference data for each of the individual polymers, it is possible to quantify mixtures of the two.
There has also been an increasing requirement for compositional profiling of these complex materials. Profiling with monatomic argon can result in a high degree of chemical modification during the acquisition of depth profiles for organic materials, but it has been shown recently that the use of argon cluster beams for depth profiling can preserve chemical information during analysis of organic materials. This talk will present data from cluster profiling studies of polymer blends, using XPS valence band analysis to quantify the polymeric mixtures during the profile.