X-ray Microscopy and NEXAFS Spectroscopy of Macrophase-Separated Random Block Copolymer/Homopolymer Blends

Morphological characterization of bulk polymer blends or compatibilized alloys at submicron spatial resolution has almost exclusively relied upon electron microscopy techniques. Since, however, most organic polymers are composed of carbon and light elements, an arsenal of methods to enhance phase contrast has been developed to facilitate discrimination and analysis of property-governing morphological features.1 For transmission electron microscopy (TEM), chemical modification of polymeric specimens through, for example, functional-ity-specific incorporation of heavy-metal staining agents (typically OsO4 or RuO4) may result in ambiguous results due to an inadequate understanding of the staining reaction or competing reaction kinetics. While microanalytical techniques such as light-element energy-