Hierarchical microstructures spanning multiple length scales are common in polymers and polymer composites. Microstructure control across large range of length scales is critical for performance customization. Further development and optimization of these complex microstructures requires powerful characterization tools with capabilities matching the complexity of the problem. A versatile materials microstructure and structure characterization facility at the Advanced Photon Source (APS) strives to provide such capabilities by combining Bonse-Hart ultra-small-angle X-ray scattering (USAXS) with pinhole SAXS and wide-angle X-ray scattering (WAXS) measurements. Making use of Si 440 crystal optics and high-energy X-rays, this unique combination provides characterization capabilities over 5 decades in scale range – from over 20 micrometers as an upper length scale down to below 1Å. The maximum allowable feature size matches that of contemporary ultra-small-angle neutron scattering (USANS) instruments, while the X-ray flux of 1012-13 photons/second enables rapid in situ measurements. Recent implementation of on-the-fly scanning of the USAXS instrument allows complete characterization over this entire size range in under 3 minutes with about 4 decades of larger sizes taking about 1.5 minutes. Additionally, USAXS-XPCS capabilities have been developed recently and are now available to the user community. Taking advantage of the coherence in the X-ray beam and using a 2D collimated USAXS geometry, the internal dynamics of materials can be studied with millisecond time resolution by X-ray photon correlation spectroscopy (XPCS) in USAXS-XPCS measurements over a microstructure scale range from ≈ 100nm to several micrometers. The capabilities of this technique will significantly improve when APS-MBA upgrade is finished in few years, opening the technique to wide range of weaker scattering samples. The presentation will review the current status of this versatile materials characterization facility and present scientific examples enabled by its unique capabilities.

Synchrotron facility for characterization of hierarchical structures - from microns to Angstroms in less than 3 minutes

249th National Meeting (2015)

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