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Flow Reversal in Traveling-Wave Electrokinetics: An Analysis of Forces Due to Ionic Concentration Gradients

Flow Reversal in Traveling-Wave Electrokinetics: An Analysis of Forces Due to Ionic Concentration Gradients
Flow Reversal in Traveling-Wave Electrokinetics: An Analysis of Forces Due to Ionic Concentration Gradients
Pumping of electrolytes using ac electric fields from arrays of microelectrodes is a subject of current research. The behavior of fluids at low signal amplitudes (< 2-3 V-pp) is in qualitative agreement with the prediction of the ac electroosmosis theory. At higher voltages, this theory cannot account for the experimental observations. In some cases, net pumping is generated in the direction opposite to that predicted by the theory (flow reversal). In this work, we use fluorescent dyes to study the effect of ionic concentration gradients generated by Faradaic currents. We also evaluate the influence of factors such as the channel height and microelectrode array shape in the pumping of electrolytes with traveling-wave potentials. Induced charge beyond the Debye length is postulated to be responsible for the forces generating the observed flows at higher voltages. Numerical calculations are performed in order to illustrate the mechanisms that might be responsible for generating the flow.
0743-7463
4988-4997
Garcia-Sanchez, Pablo
11cec08e-0384-4ef6-a1b3-183c9b32c4ea
Ramos, Antonio
511ab594-f312-45ce-b7ff-ef348fd9b559
Gonzalez, Antonio
41d6e3cb-9a9a-499a-89b3-a2872864e9d3
Green, Nicolas G
d9b47269-c426-41fd-a41d-5f4579faa581
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Garcia-Sanchez, Pablo
11cec08e-0384-4ef6-a1b3-183c9b32c4ea
Ramos, Antonio
511ab594-f312-45ce-b7ff-ef348fd9b559
Gonzalez, Antonio
41d6e3cb-9a9a-499a-89b3-a2872864e9d3
Green, Nicolas G
d9b47269-c426-41fd-a41d-5f4579faa581
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174

Garcia-Sanchez, Pablo, Ramos, Antonio, Gonzalez, Antonio, Green, Nicolas G and Morgan, Hywel (2009) Flow Reversal in Traveling-Wave Electrokinetics: An Analysis of Forces Due to Ionic Concentration Gradients. Langmuir, 25 (9), 4988-4997. (doi:10.1021/la803651e).

Record type: Article

Abstract

Pumping of electrolytes using ac electric fields from arrays of microelectrodes is a subject of current research. The behavior of fluids at low signal amplitudes (< 2-3 V-pp) is in qualitative agreement with the prediction of the ac electroosmosis theory. At higher voltages, this theory cannot account for the experimental observations. In some cases, net pumping is generated in the direction opposite to that predicted by the theory (flow reversal). In this work, we use fluorescent dyes to study the effect of ionic concentration gradients generated by Faradaic currents. We also evaluate the influence of factors such as the channel height and microelectrode array shape in the pumping of electrolytes with traveling-wave potentials. Induced charge beyond the Debye length is postulated to be responsible for the forces generating the observed flows at higher voltages. Numerical calculations are performed in order to illustrate the mechanisms that might be responsible for generating the flow.

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Published date: 2009
Additional Information: Imported from ISI Web of Science
Organisations: Electronics & Computer Science

Identifiers

Local EPrints ID: 270024
URI: http://eprints.soton.ac.uk/id/eprint/270024
ISSN: 0743-7463
PURE UUID: b0221ae9-825f-451f-b78d-2db289572e5b
ORCID for Nicolas G Green: ORCID iD orcid.org/0000-0001-9230-4455
ORCID for Hywel Morgan: ORCID iD orcid.org/0000-0003-4850-5676

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Date deposited: 21 Apr 2010 07:46
Last modified: 15 Mar 2024 03:20

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Contributors

Author: Pablo Garcia-Sanchez
Author: Antonio Ramos
Author: Antonio Gonzalez
Author: Nicolas G Green ORCID iD
Author: Hywel Morgan ORCID iD

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