| AVS 65th International Symposium & Exhibition | |
| Applied Surface Science Division | Wednesday Sessions |
| Session AS+SE-WeA |
| Session: | Industrial and Practical Applications of Surface Analysis |
| Presenter: | Steven Pachuta, 3M Company |
| Authors: | S.J. Pachuta, 3M Company D.M. Poirier, 3M Company |
| Correspondent: | Click to Email |
Surface chemistry is often key to the performance of materials like films, coatings, and adhesives. Controlling and understanding surface chemistry is therefore critical to manufacturers. X-ray photoelectron spectroscopy (XPS) is the workhorse in industrial surface characterization laboratories, followed closely by time-of-flight secondary ion mass spectrometry (ToF-SIMS). XPS survey spectra provide quantitative elemental information on surfaces, and XPS high energy-resolution spectra can give information on chemical states. ToF-SIMS, in general, gives even more specific surface chemical information, such as the identities of polymer additives and surface contaminants.
This presentation will describe efforts to increase the chemical specificity of both XPS and ToF-SIMS for organic species, especially polymers. The XPS valence band region contains a complex fingerprint which is highly dependent on molecular structure. By using databases in combination with multivariate methods such as principal component analysis (PCA) and partial least squares (PLS), a surprising degree of information can be extracted from valence band spectra of unknown materials.
The fact that many real-world surfaces comprise a mixture of components is a recurrent frustration in industrial surface characterization. ToF-SIMS analysts have long envied their GC/MS and LC/MS counterparts, who have the luxury of separating mixtures before doing mass spectrometry. The recent commercial availability of tandem mass spectrometry (MS/MS) on ToF-SIMS instruments has gone some way towards addressing the mixture problem and has increased the ability of ToF-SIMS to identify unknown materials. Examples will be presented.