Document Detail


Modeling of combined electroosmotic and capillary flow in microchannels.
MedLine Citation:
PMID:  20206000     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the present study, theoretical model for the transient response of a capillary flow under the combined effects of electroosmotic and capillary forces at low Reynolds number is presented. The governing equation is derived based on the balance among the electrokinetic, surface, viscous and gravity forces. A non-dimensional transient governing equation for the penetration depth as a function of time is obtained by normalizing the viscous, gravity and electroosmotic forces with surface tension force. A new non-dimensional group for the electroosmotic force, E(o), is obtained through the non-dimensional analysis. This new non-dimensional group is a representation of combined electroosmosis and surface tension, i.e., capillarity. The numerical solution of governing equation is obtained to study the effect of different operating parameters on the flow front transport. In a combined flow, it is observed that the flow with positive and low negative magnitude E(o) numbers, the attainment of equilibrium penetration depth is similar to a capillary flow. In case of high negative magnitude E(o) numbers, complete filling of the channel is observed. The electrolyte with lower permittivity delays the progress of the flow front whereas a large EDL transports the electrolyte quickly. Higher viscous and gravity forces also delay the transport process in the combined flow. This model suggests that in combined flow the electrokinetic parameters also play an important role on the capillary flow and experiments are required to confirm this electrokinetic effect on capillary transport.
Authors:
Prashant R Waghmare; Sushanta K Mitra
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-02-06
Journal Detail:
Title:  Analytica chimica acta     Volume:  663     ISSN:  1873-4324     ISO Abbreviation:  Anal. Chim. Acta     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-08     Completed Date:  2010-06-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370534     Medline TA:  Anal Chim Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  117-26     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Elsevier B.V. All rights reserved.
Affiliation:
Micro and Nano-scale Transport Laboratory, Department of Mechanical Engineering, University of Alberta, Edmonton, Canada T6G 2G8.
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MeSH Terms
Descriptor/Qualifier:
Chromatography, Micellar Electrokinetic Capillary / methods*
Electrolytes / chemistry
Electroosmosis / methods*
Microfluidic Analytical Techniques / methods*
Models, Chemical*
Surface Tension
Time Factors
Chemical
Reg. No./Substance:
0/Electrolytes

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