Direction-dependent dynamics of colloidal particle pairs and the Stokes-Einstein relation in quasi-two-dimensional fluids.

Autor: Barbhuiya NH; Department of Physics, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382055, Gujarat, India., Yodh AG; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, 19104, PA, USA., Mishra CK; Department of Physics, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382055, Gujarat, India. chandan.mishra@iitgn.ac.in.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2023 Aug 22; Vol. 14 (1), pp. 5109. Date of Electronic Publication: 2023 Aug 22.
DOI: 10.1038/s41467-023-40772-2
Abstrakt: Hydrodynamic interactions are important for diverse fluids, especially those with low Reynolds number such as microbial and particle-laden suspensions, and proteins diffusing in membranes. Unfortunately, while far-field (asymptotic) hydrodynamic interactions are fully understood in two- and three-dimensions, near-field interactions are not, and thus our understanding of motions in dense fluid suspensions is still lacking. In this contribution, we experimentally explore the hydrodynamic correlations between particles in quasi-two-dimensional colloidal fluids in the near-field. Surprisingly, the measured displacement and relaxation of particle pairs in the body frame exhibit direction-dependent dynamics that can be connected quantitatively to the measured near-field hydrodynamic interactions. These findings, in turn, suggest a mechanism for how and when hydrodynamics can lead to a breakdown of the ubiquitous Stokes-Einstein relation (SER). We observe this breakdown, and we show that the direction-dependent breakdown of the SER is ameliorated along directions where hydrodynamic correlations are smallest. In total, the work uncovers significant ramifications of near-field hydrodynamics on transport and dynamic restructuring of fluids in two-dimensions.
(© 2023. Springer Nature Limited.)
Databáze: MEDLINE
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