In many applications of soft matter, the connection between structure and performance is complex, and conventional structure measurements are not sufficient to provide a predictive structural model. Nanoscale variations in molecular orientation and composition, particularly in amorphous regions, are thought to be critical, but few techniques can probe them. Although advanced electron microscopy approaches are approaching molecular length scales, these incredibly useful techniques still lack the ability to probe orientation in amorphous organic domains.<br/><br/>I will describe our approach to polarized resonant soft X-ray scattering (P-RSoXS), which combines principles of spectroscopy, small-angle scattering, real-space imaging by electron microscopy, and molecular simulation to produce a nanoscale orientation measurement for soft materials and complex fluids. The principles of this emerging technique will be discussed, as well as practical aspects of the P-RSoXS experiment and data interpretation. Progress and designs for a new P-RSoXS beamline will be shown.<br/><br/>Examples will include semicrystalline polyolefins, for which the goal is to measure orientation in the interlamellar amorphous regions, and therapeutic micelles, for which the goal is to probe orientational order in solution self-assembly. An emphasis will be placed on connections between P-RSoXS and small angle neutron scattering (SANS), including different contrast approaches, different experimental considerations, and unique measurement capabilities of each technique.

Soft matter structure measurement by polarized resonant soft X-ray scattering

256th National Meeting (2018)

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