Concentration-polarization electroosmosis near insulating constrictions within microfluidic channels
Concentration-polarization electroosmosis near insulating constrictions within microfluidic channels
Electric fields are commonly used to trap and separate micro- and nanoparticles near channel constrictions in microfluidic devices. The trapping mechanism is attributed to the electrical forces arising from the nonhomogeneous electric field caused by the constrictions, and the phenomenon is known as insulator-based-dielectrophoresis (iDEP). In this paper, we describe stationary electroosmotic flows of electrolytes around insulating constrictions induced by low frequency AC electric fields (below 10 kHz). Experimental characterization of the flows is described for two different channel heights (50 and 10 μm), together with numerical simulations based on an electrokinetic model that considers the modification of the local ionic concentration due to surface conductance on charged insulating walls. We term this phenomenon concentration-polarization electroosmosis (CPEO). The observed flow characteristics are in qualitative agreement with the predictions of this model. However, for shallow channels (10 μm), trapping of the particles on both sides of the constrictions is also observed. This particle and fluid behavior could play a major role in iDEP and could be easily misinterpreted as a dielectrophoretic force.
14667-14674
Fernández-Mateo, Raúl
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Calero, Víctor
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Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Ramos, Antonio
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García-Sánchez, Pablo
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9 November 2021
Fernández-Mateo, Raúl
f287538e-c53c-4208-b8bf-945b0966fd5f
Calero, Víctor
b2e82567-e1f1-466d-a283-3517a4a9e71b
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Ramos, Antonio
7a983b1e-4835-4dfe-9aa5-502cef051c31
García-Sánchez, Pablo
1dd0c963-1e9f-41a2-9aea-db9ba09d757c
Fernández-Mateo, Raúl, Calero, Víctor, Morgan, Hywel, Ramos, Antonio and García-Sánchez, Pablo
(2021)
Concentration-polarization electroosmosis near insulating constrictions within microfluidic channels.
Analytical Chemistry, 93 (44), .
(doi:10.1021/acs.analchem.1c02849).
Abstract
Electric fields are commonly used to trap and separate micro- and nanoparticles near channel constrictions in microfluidic devices. The trapping mechanism is attributed to the electrical forces arising from the nonhomogeneous electric field caused by the constrictions, and the phenomenon is known as insulator-based-dielectrophoresis (iDEP). In this paper, we describe stationary electroosmotic flows of electrolytes around insulating constrictions induced by low frequency AC electric fields (below 10 kHz). Experimental characterization of the flows is described for two different channel heights (50 and 10 μm), together with numerical simulations based on an electrokinetic model that considers the modification of the local ionic concentration due to surface conductance on charged insulating walls. We term this phenomenon concentration-polarization electroosmosis (CPEO). The observed flow characteristics are in qualitative agreement with the predictions of this model. However, for shallow channels (10 μm), trapping of the particles on both sides of the constrictions is also observed. This particle and fluid behavior could play a major role in iDEP and could be easily misinterpreted as a dielectrophoretic force.
Text
acs.analchem.1c02849
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e-pub ahead of print date: 27 October 2021
Published date: 9 November 2021
Additional Information:
Funding Information:
P.G.S. and A.R. acknowledge financial support by ERDF and Spanish Research Agency MCI under contract PGC2018-099217-B-I00. We also thank Katie Chamberlain for making the PDMS masters.
Identifiers
Local EPrints ID: 469984
URI: http://eprints.soton.ac.uk/id/eprint/469984
ISSN: 0003-2700
PURE UUID: 84fd1ad1-05bb-46cd-8db5-3523905ad363
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Date deposited: 29 Sep 2022 16:47
Last modified: 18 Mar 2024 02:58
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Contributors
Author:
Raúl Fernández-Mateo
Author:
Víctor Calero
Author:
Hywel Morgan
Author:
Antonio Ramos
Author:
Pablo García-Sánchez
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