Chemical Mapping of Polymer Microstructure Using Soft X-ray Spectromicroscopy

Recently, synchrotron-based soft X-ray spectromicroscopy techniques have been applied to studies of polymer microstructure at the ~50 nm spatial scale. Functional group based chemical speciation and quantitative mapping is provided by near edge X-ray absorption fine structure spectral (NEXAFS) contrast. The techniques, sample data, and analysis methods of scanning transmission X-ray microscopy (STXM) and X-ray photoemission electron microscopy (X-PEEM) are outlined. The capabilities of STXM are illustrated by results from recent studies of (a) controlled release microcapsules and microspheres, (b) microcapsules being developed for gene therapy applications, (c) conducting polymer films studied in the presence of electrolyte and under potential control, and (d) studies of protein interactions with patterned polymer surfaces. In the latter area, the capabilities of STXM and X-PEEM are compared directly.