Self-diffusion of nonspherical particles fundamentally conflicts with effective sphere models
Roosen-Runge, Felix LU ; Schurtenberger, Peter LU
and Stradner, Anna
LU
(2021)
In Journal of Physics: Condensed Matter
33(15).
- Abstract
Modeling diffusion of nonspherical particles presents an unsolved and considerable challenge, despite its importance for the understanding of crowding effects in biology, food technology and formulation science. A common approach in experiment and simulation is to map nonspherical objects on effective spheres to subsequently use the established predictions for spheres to approximate phenomena for nonspherical particles. Using numerical evaluation of the hydrodynamic mobility tensor, we show that this so-called effective sphere model fundamentally fails to represent the self-diffusion in solutions of ellipsoids as well as rod-like assemblies of spherical beads. The effective sphere model drastically overestimates the slowing down of... (More)
Modeling diffusion of nonspherical particles presents an unsolved and considerable challenge, despite its importance for the understanding of crowding effects in biology, food technology and formulation science. A common approach in experiment and simulation is to map nonspherical objects on effective spheres to subsequently use the established predictions for spheres to approximate phenomena for nonspherical particles. Using numerical evaluation of the hydrodynamic mobility tensor, we show that this so-called effective sphere model fundamentally fails to represent the self-diffusion in solutions of ellipsoids as well as rod-like assemblies of spherical beads. The effective sphere model drastically overestimates the slowing down of self-diffusion down to volume fractions below 0.01. Furthermore, even the linear term relevant at lower volume fraction is inaccurate, linked to a fundamental misconception of effective sphere models. To overcome the severe problems related with the use of effective sphere models, we suggest a protocol to predict the short-time self-diffusion of rod-like systems, based on simulations with hydrodynamic interactions that become feasible even for more complex molecules as the essential observable shows a negligible system-size effect.
(Less)
- author
- Roosen-Runge, Felix
LU
; Schurtenberger, Peter
LU
and Stradner, Anna
LU
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- crowding effects, diffusion, effective sphere models, hydrodynamic interactions, nonspherical particles, particle mobility
- in
- Journal of Physics: Condensed Matter
- volume
- 33
- issue
- 15
- article number
- 154002
- publisher
- IOP Publishing
- external identifiers
-
- pmid:33498038
- scopus:85103565717
- ISSN
- 0953-8984
- DOI
- 10.1088/1361-648X/abdff9
- language
- English
- LU publication?
- yes
- id
- c7ad288c-32d8-4139-98f6-ed0474034a40
- date added to LUP
- 2021-04-12 09:26:21
- date last changed
- 2024-06-15 09:39:54
@article{c7ad288c-32d8-4139-98f6-ed0474034a40,
abstract = {{<p>Modeling diffusion of nonspherical particles presents an unsolved and considerable challenge, despite its importance for the understanding of crowding effects in biology, food technology and formulation science. A common approach in experiment and simulation is to map nonspherical objects on effective spheres to subsequently use the established predictions for spheres to approximate phenomena for nonspherical particles. Using numerical evaluation of the hydrodynamic mobility tensor, we show that this so-called effective sphere model fundamentally fails to represent the self-diffusion in solutions of ellipsoids as well as rod-like assemblies of spherical beads. The effective sphere model drastically overestimates the slowing down of self-diffusion down to volume fractions below 0.01. Furthermore, even the linear term relevant at lower volume fraction is inaccurate, linked to a fundamental misconception of effective sphere models. To overcome the severe problems related with the use of effective sphere models, we suggest a protocol to predict the short-time self-diffusion of rod-like systems, based on simulations with hydrodynamic interactions that become feasible even for more complex molecules as the essential observable shows a negligible system-size effect. </p>}},
author = {{Roosen-Runge, Felix and Schurtenberger, Peter and Stradner, Anna}},
issn = {{0953-8984}},
keywords = {{crowding effects; diffusion; effective sphere models; hydrodynamic interactions; nonspherical particles; particle mobility}},
language = {{eng}},
number = {{15}},
publisher = {{IOP Publishing}},
series = {{Journal of Physics: Condensed Matter}},
title = {{Self-diffusion of nonspherical particles fundamentally conflicts with effective sphere models}},
url = {{http://dx.doi.org/10.1088/1361-648X/abdff9}},
doi = {{10.1088/1361-648X/abdff9}},
volume = {{33}},
year = {{2021}},
}