Wall repulsion of charged colloidal particles during electrophoresis in microfluidic channels
Wall repulsion of charged colloidal particles during electrophoresis in microfluidic channels
Electrophoresis describes the motion of charged particles suspended in electrolytes when subjected to an external electric field. Previous experiments have shown that particles undergoing electrophoresis are repelled from nearby channel walls, contrary to the standard description of electrophoresis that predicts no hydrodynamic repulsion. Dielectrophoretic (DEP) repulsive forces have been commonly invoked as the cause of this wall repulsion. We show that DEP forces can only account for this wall repulsion at high frequencies of applied electric field. In the presence of a low-frequency field, quadrupolar electro-osmotic flows are observed around the particles. We experimentally demonstrate that these hydrodynamic flows are the cause of the widely observed particle-wall interaction. This hydrodynamic wall repulsion should be considered in the design and application of electric-field-driven manipulation of particles in microfluidic devices.
Fernandez-Mateo, Raul
f287538e-c53c-4208-b8bf-945b0966fd5f
Calero, Víctor
4c270680-a83d-4c15-9cc6-df3fd34b79df
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Garcia-Sanchez, Pablo
11cec08e-0384-4ef6-a1b3-183c9b32c4ea
Ramos, Antonio
79d60433-0c6b-4eaa-80ac-e2f61e704f72
16 February 2022
Fernandez-Mateo, Raul
f287538e-c53c-4208-b8bf-945b0966fd5f
Calero, Víctor
4c270680-a83d-4c15-9cc6-df3fd34b79df
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Garcia-Sanchez, Pablo
11cec08e-0384-4ef6-a1b3-183c9b32c4ea
Ramos, Antonio
79d60433-0c6b-4eaa-80ac-e2f61e704f72
Fernandez-Mateo, Raul, Calero, Víctor, Morgan, Hywel, Garcia-Sanchez, Pablo and Ramos, Antonio
(2022)
Wall repulsion of charged colloidal particles during electrophoresis in microfluidic channels.
Physical Review Letters, 128 (7), [074501].
(doi:10.1103/PhysRevLett.128.074501).
Abstract
Electrophoresis describes the motion of charged particles suspended in electrolytes when subjected to an external electric field. Previous experiments have shown that particles undergoing electrophoresis are repelled from nearby channel walls, contrary to the standard description of electrophoresis that predicts no hydrodynamic repulsion. Dielectrophoretic (DEP) repulsive forces have been commonly invoked as the cause of this wall repulsion. We show that DEP forces can only account for this wall repulsion at high frequencies of applied electric field. In the presence of a low-frequency field, quadrupolar electro-osmotic flows are observed around the particles. We experimentally demonstrate that these hydrodynamic flows are the cause of the widely observed particle-wall interaction. This hydrodynamic wall repulsion should be considered in the design and application of electric-field-driven manipulation of particles in microfluidic devices.
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Wall_Repulsion_in_Electrophoresis__AcceptedManuscript
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PhysRevLett.128.074501
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Accepted/In Press date: 18 January 2022
Published date: 16 February 2022
Additional Information:
Funding Information:
V. C., P. G. S., and A. R. acknowledge Grant PGC2018-099217-B-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe.”
Publisher Copyright:
© 2022 American Physical Society.
Identifiers
Local EPrints ID: 456541
URI: http://eprints.soton.ac.uk/id/eprint/456541
ISSN: 1079-7114
PURE UUID: 689686fa-a6c8-4dad-9445-8aef14a24c80
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Date deposited: 04 May 2022 17:18
Last modified: 06 Jun 2024 01:42
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Contributors
Author:
Raul Fernandez-Mateo
Author:
Víctor Calero
Author:
Hywel Morgan
Author:
Pablo Garcia-Sanchez
Author:
Antonio Ramos
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