Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions

Electroosmotic flow (EOF) with two or more fluids is often encountered in various microfluidic applications. However, no investigation has hitherto been conducted to investigate the hysteretic or flow direction-dependent behavior during displacement flow of solutions with dissimilar anion species. I...

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Main Authors: Lim, An Eng, Lim, Chun Yee, Lam, Yee Cheong
Other Authors: School of Mechanical and Aerospace Engineering
Format: Article
Language:English
Published: 2017
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Online Access:https://hdl.handle.net/10356/83063
http://hdl.handle.net/10220/42418
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-830632023-03-04T17:14:43Z Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions Lim, An Eng Lim, Chun Yee Lam, Yee Cheong School of Mechanical and Aerospace Engineering Finite element method Electrolytes Electroosmotic flow (EOF) with two or more fluids is often encountered in various microfluidic applications. However, no investigation has hitherto been conducted to investigate the hysteretic or flow direction-dependent behavior during displacement flow of solutions with dissimilar anion species. In this investigation, EOF of dissimilar anionic solutions was studied experimentally through the current monitoring method and numerically through finite element simulations. As opposed to other conventional displacement flows, EOF involving dissimilar anionic solutions exhibits counterintuitive behavior, whereby the current–time curve does not reach the steady-state value of the displacing electrolyte. Two distinct mechanics have been identified as the causes for this observation: (a) ion concentration adjustment when the displacing anions migrate upstream against EOF due to competition between the gradients of electromigrative and convective fluxes and (b) ion concentration readjustment induced by the static diffusive interfacial region between the dissimilar fluids which can only be propagated throughout the entire microchannel with the presence of EOF. The resultant ion distributions lead to the flow rate to be directional-dependent, indicating that the flow conditions are asymmetric between these two different flow directions. The outcomes of this investigation contribute to the in-depth understanding of flow behavior in microfluidic systems involving inhomogeneous fluids, particularly dissimilar anionic solutions. The understanding of EOF hysteresis is fundamentally important for the accurate prediction of analytes transport in microfluidic devices under EOF. Accepted version 2017-05-15T05:53:20Z 2019-12-06T15:11:04Z 2017-05-15T05:53:20Z 2019-12-06T15:11:04Z 2016 2016 Journal Article Lim, A. E., Lim, C. Y., & Lam, Y. C. (2016). Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions. Analytical Chemistry, 88(16), 8064-8073. 0003-2700 https://hdl.handle.net/10356/83063 http://hdl.handle.net/10220/42418 10.1021/acs.analchem.6b01536 200067 en Analytical Chemistry © 2016 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by Analytical Chemistry, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/acs.analchem.6b01536]. 16 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Finite element method
Electrolytes
spellingShingle Finite element method
Electrolytes
Lim, An Eng
Lim, Chun Yee
Lam, Yee Cheong
Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
description Electroosmotic flow (EOF) with two or more fluids is often encountered in various microfluidic applications. However, no investigation has hitherto been conducted to investigate the hysteretic or flow direction-dependent behavior during displacement flow of solutions with dissimilar anion species. In this investigation, EOF of dissimilar anionic solutions was studied experimentally through the current monitoring method and numerically through finite element simulations. As opposed to other conventional displacement flows, EOF involving dissimilar anionic solutions exhibits counterintuitive behavior, whereby the current–time curve does not reach the steady-state value of the displacing electrolyte. Two distinct mechanics have been identified as the causes for this observation: (a) ion concentration adjustment when the displacing anions migrate upstream against EOF due to competition between the gradients of electromigrative and convective fluxes and (b) ion concentration readjustment induced by the static diffusive interfacial region between the dissimilar fluids which can only be propagated throughout the entire microchannel with the presence of EOF. The resultant ion distributions lead to the flow rate to be directional-dependent, indicating that the flow conditions are asymmetric between these two different flow directions. The outcomes of this investigation contribute to the in-depth understanding of flow behavior in microfluidic systems involving inhomogeneous fluids, particularly dissimilar anionic solutions. The understanding of EOF hysteresis is fundamentally important for the accurate prediction of analytes transport in microfluidic devices under EOF.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Lim, An Eng
Lim, Chun Yee
Lam, Yee Cheong
format Article
author Lim, An Eng
Lim, Chun Yee
Lam, Yee Cheong
author_sort Lim, An Eng
title Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
title_short Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
title_full Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
title_fullStr Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
title_full_unstemmed Electroosmotic Flow Hysteresis for Dissimilar Anionic Solutions
title_sort electroosmotic flow hysteresis for dissimilar anionic solutions
publishDate 2017
url https://hdl.handle.net/10356/83063
http://hdl.handle.net/10220/42418
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