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Microsecond hydrodynamic interactions in dense colloidal dispersions probed at the European XFEL

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journal contribution
posted on 13.10.2021, 04:14 by F Dallari, A Jain, M Sikorski, J Möller, R Bean, U Boesenberg, L Frenzel, C Goy, J Hallmann, Y Kim, I Lokteva, V Markmann, G Mills, A Rodriguez-Fernandez, W Roseker, M Scholz, R Shayduk, P Vagovic, M Walther, F Westermeier, A Madsen, Adrian MancusoAdrian Mancuso, G Grübel, F Lehmkühler
Many soft-matter systems are composed of macromolecules or nanoparticles suspended in water. The characteristic times at intrinsic length scales of a few nanometres fall therefore in the microsecond and sub-microsecond time regimes. With the development of free-electron lasers (FELs) and fourth-generation synchrotron light-sources, time-resolved experiments in such time and length ranges will become routinely accessible in the near future. In the present work we report our findings on prototypical soft-matter systems, composed of charge-stabilized silica nanoparticles dispersed in water, with radii between 12 and 15 nm and volume fractions between 0.005 and 0.2. The sample dynamics were probed by means of X-ray photon correlation spectroscopy, employing the megahertz pulse repetition rate of the European XFEL and the Adaptive Gain Integrating Pixel Detector. We show that it is possible to correctly identify the dynamical properties that determine the diffusion constant, both for stationary samples and for systems driven by XFEL pulses. Remarkably, despite the high photon density the only observable induced effect is the heating of the scattering volume, meaning that all other X-ray induced effects do not influence the structure and the dynamics on the probed timescales. This work also illustrates the potential to control such induced heating and it can be predicted with thermodynamic models.

Funding

This work is supported by the Cluster of Excellence `Advanced Imaging of Matter' of the Deutsche Forschungsgemeinschaft (DFG), EXC 2056, (project No. 390715994).

History

Publication Date

01/09/2021

Journal

IUCrJ

Volume

8

Issue

5

Pagination

775-783

Publisher

International Union of Crystallography

ISSN

2052-2525

Rights Statement

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.