Memory-induced alignment of colloidal dumbbells

Fuente: arXiv
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Main Authors: Kumar, Karthika Krishna, Caspers, Juliana, Ginot, Félix, Krüger, Matthias, Bechinger, Clemens
Format: Preprint
Published: 2023
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_version_ 1866909090519711744
author Kumar, Karthika Krishna
Caspers, Juliana
Ginot, Félix
Krüger, Matthias
Bechinger, Clemens
author_facet Kumar, Karthika Krishna
Caspers, Juliana
Ginot, Félix
Krüger, Matthias
Bechinger, Clemens
contents When a colloidal probe is forced through a viscoelastic fluid which is characterized by a long stress-relaxation time, the fluid is excited out of equilibrium. This is leading to a number of interesting effects including a non-trivial recoil of the probe when the driving force is removed. Here, we experimentally and theoretically investigate the transient recoil dynamics of non-spherical particles, i.e., colloidal dumbbells. In addition to a translational recoil of the dumbbells, we also find a pronounced angular reorientation which results from the relaxation of the surrounding fluid. Our findings are in good agreement with a Langevin description based on the symmetries of a director (dumbbell) as well as a microscopic bath-rod model. Remarkably, we find a frustrated state with amplified fluctuations when the dumbbell is oriented perpendicular to the direction of driving. Our results demonstrate the complex behavior of non-spherical objects within a relaxing environment which are of immediate interest for the motion of externally but also self-driven asymmetric objects in viscoelastic fluids.
format Preprint
id arxiv_https___arxiv_org_abs_2308_16023
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Memory-induced alignment of colloidal dumbbells
Kumar, Karthika Krishna
Caspers, Juliana
Ginot, Félix
Krüger, Matthias
Bechinger, Clemens
Soft Condensed Matter
Statistical Mechanics
When a colloidal probe is forced through a viscoelastic fluid which is characterized by a long stress-relaxation time, the fluid is excited out of equilibrium. This is leading to a number of interesting effects including a non-trivial recoil of the probe when the driving force is removed. Here, we experimentally and theoretically investigate the transient recoil dynamics of non-spherical particles, i.e., colloidal dumbbells. In addition to a translational recoil of the dumbbells, we also find a pronounced angular reorientation which results from the relaxation of the surrounding fluid. Our findings are in good agreement with a Langevin description based on the symmetries of a director (dumbbell) as well as a microscopic bath-rod model. Remarkably, we find a frustrated state with amplified fluctuations when the dumbbell is oriented perpendicular to the direction of driving. Our results demonstrate the complex behavior of non-spherical objects within a relaxing environment which are of immediate interest for the motion of externally but also self-driven asymmetric objects in viscoelastic fluids.
title Memory-induced alignment of colloidal dumbbells
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2308.16023