Hydrodynamic approximations for driven dense colloidal mixtures in narrow pores

Fuente: arXiv
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Main Authors: Slanina, Frantisek, Kotrla, Miroslav
Format: Preprint
Published: 2025
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author Slanina, Frantisek
Kotrla, Miroslav
author_facet Slanina, Frantisek
Kotrla, Miroslav
contents The system of driven dense colloid mixtures is studied in one-, two- and three-dimensional geometries. We calculate the diffusion coefficients and mobilities for each particle type, including cross-terms, in a hydrodynamic limit, using a mean-field-type approximation. The set of non-linear diffusion equations are then solved. In one dimension, analytical results are possible. We show that in mixtures, the ``Brazil nut'' phenomenon, or depletion of larger particles by force of smaller ones, appears quite generically. We calculate the ratchet current and quantify the capability of sorting particles according to their size. We also indicate that the ``Brazil nut'' effect lies behind the possibility of perfect separation, where large and big particles travel in strictly opposite direction.
format Preprint
id arxiv_https___arxiv_org_abs_2508_09686
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hydrodynamic approximations for driven dense colloidal mixtures in narrow pores
Slanina, Frantisek
Kotrla, Miroslav
Statistical Mechanics
Soft Condensed Matter
The system of driven dense colloid mixtures is studied in one-, two- and three-dimensional geometries. We calculate the diffusion coefficients and mobilities for each particle type, including cross-terms, in a hydrodynamic limit, using a mean-field-type approximation. The set of non-linear diffusion equations are then solved. In one dimension, analytical results are possible. We show that in mixtures, the ``Brazil nut'' phenomenon, or depletion of larger particles by force of smaller ones, appears quite generically. We calculate the ratchet current and quantify the capability of sorting particles according to their size. We also indicate that the ``Brazil nut'' effect lies behind the possibility of perfect separation, where large and big particles travel in strictly opposite direction.
title Hydrodynamic approximations for driven dense colloidal mixtures in narrow pores
topic Statistical Mechanics
Soft Condensed Matter
url https://arxiv.org/abs/2508.09686