NSLS-II Collquium

"Resonant x-ray scattering from soft materials as a probe of molecular orientation fluctuations at the nanoscale"

Presented by Noel A. Clark, University of Colorado, Boulder

Thursday, February 14, 2019, 4:00 pm — Large Seminar Room, Bldg. 510

Orientation fluctuations are ubiquitous features of soft materials on length scales ranging from nanometers in the rotational dynamics of single molecules, to the macroscopic deformation of local orientational order in liquid crystals, polymers, and biomaterials. Here we present the application of depolarized resonant soft x-ray scattering (DRSoXS) as a selective probe of molecular orientation fluctuations at the nanoscale. This technique is demonstrated by determination of the wavevector spectrum of thermally generated collective reorientations in a nematic liquid crystal using Carbon K??-edge resonant scattering (incident wavelength = 4.4nm). DRSOXS uniquely reveals transient, short-range heliconical molecular assemblies and their pretransitional development, as ordering into a chiral three-dimensional helical state is approached.

Hosted by: John Hill

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