Capabilities at the APS for Research in Polymer Science
Jin Wang
Advanced Photon Source, Argonne National Laboratory
X-ray scattering, as a complimentary technique to light and neutron scattering, is powerful for studying structures and dynamics in polymers, their composites and thin films. Synthesizing complex nanocomposites and superstructures of polymers is of great interest in biology, chemistry, physics and engineering applications such as the fabrication of novel electronic, magnetic, and photonic devices. Fundamental understanding will be necessary to control the formation of these superstructures using polymers on all length scales (nano, micro, and macro) whether the structure is fabricated or self-assembled. The most widely used tools to study bulk polymer structures at the Advanced Photon Source (APS) include small-angle x-ray scattering (SAXS), wide-angle x-ray scattering (WAXS) and ultra small-angle x-ray scattering (USAXS) to probe polymer structures on those length scales. With high-intensity x-ray beams at the APS, the measurements in the real-time domain give considerable insight into the kinetics and interactions on molecular level. High coherence and flexible timing structure are the unique characteristics of the 3rd generation synchrotron source such as the APS, promising opportunities for developing new and innovative research tools for polymer science. X-ray photon correlation spectroscopy (XPCS), in conjunction with SAXS, has been developed for studying polymer dynamics on time-scale from microseconds to seconds and on nanometer to micrometer length scale, which is difficult to cover by conventional inelastic neutron scattering and dynamic light scattering. Recently, self-assembly processes using nano to meso phase behaviors of polymer ultrathin films require measurements of their structure in situ and in real time with nanometer spatial resolution and millisecond to second temporal resolution. As an increasingly important structural characterization technique, grazing-incidence small-angle x-ray scattering (GISAXS) have found vast applications in research of polymeric materials in nanostructures and nanocomposites at surfaces and interfaces. Dedicated GISAXS beamlines have been developed at the APS to satisfy the growing demands of characterizing polymer-based complex structures. Such dedicated and state-of-the-art instruments at the APS will facilitate the fundamental understanding of the structure-function relationship in polymer thin films and nanostructures.
This work and the use of the APS are supported by the U.S. DOE under contract W-31-109-ENG-38.