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Electroosmotic Flow Reversal Outside Glass Nanopores
[Image: see text] We report observations of a striking reversal in the direction of electroosmotic flow (EOF) outside a conical glass nanopore as a function of salt concentration. At high ionic strengths (>100 mM), we observe EOF in the expected direction as predicted by classical electrokinetic...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2014
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296923/ https://www.ncbi.nlm.nih.gov/pubmed/25490120 http://dx.doi.org/10.1021/nl504237k |
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author | Laohakunakorn, Nadanai Thacker, Vivek V. Muthukumar, Murugappan Keyser, Ulrich F. |
author_facet | Laohakunakorn, Nadanai Thacker, Vivek V. Muthukumar, Murugappan Keyser, Ulrich F. |
author_sort | Laohakunakorn, Nadanai |
collection | PubMed |
description | [Image: see text] We report observations of a striking reversal in the direction of electroosmotic flow (EOF) outside a conical glass nanopore as a function of salt concentration. At high ionic strengths (>100 mM), we observe EOF in the expected direction as predicted by classical electrokinetic theory, while at low salt concentrations (<1 mM) the direction of the flow is reversed. The critical crossover salt concentration depends on the pore diameter. Finite-element simulations indicate a competition between the EOF generated from the inner and outer walls of the pore, which drives flows in opposite directions. We have developed a simple analytical model which reveals that, as the salt concentration is reduced, the flow rates inside the pore are geometrically constrained, whereas there is no such limit for flows outside the pore. This model captures all of the essential physics of the system and explains the observed data, highlighting the key role the external environment plays in determining the overall electroosmotic behavior. |
format | Online Article Text |
id | pubmed-4296923 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-42969232015-12-09 Electroosmotic Flow Reversal Outside Glass Nanopores Laohakunakorn, Nadanai Thacker, Vivek V. Muthukumar, Murugappan Keyser, Ulrich F. Nano Lett [Image: see text] We report observations of a striking reversal in the direction of electroosmotic flow (EOF) outside a conical glass nanopore as a function of salt concentration. At high ionic strengths (>100 mM), we observe EOF in the expected direction as predicted by classical electrokinetic theory, while at low salt concentrations (<1 mM) the direction of the flow is reversed. The critical crossover salt concentration depends on the pore diameter. Finite-element simulations indicate a competition between the EOF generated from the inner and outer walls of the pore, which drives flows in opposite directions. We have developed a simple analytical model which reveals that, as the salt concentration is reduced, the flow rates inside the pore are geometrically constrained, whereas there is no such limit for flows outside the pore. This model captures all of the essential physics of the system and explains the observed data, highlighting the key role the external environment plays in determining the overall electroosmotic behavior. American Chemical Society 2014-12-09 2015-01-14 /pmc/articles/PMC4296923/ /pubmed/25490120 http://dx.doi.org/10.1021/nl504237k Text en Copyright © 2014 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Laohakunakorn, Nadanai Thacker, Vivek V. Muthukumar, Murugappan Keyser, Ulrich F. Electroosmotic Flow Reversal Outside Glass Nanopores |
title | Electroosmotic Flow Reversal Outside Glass Nanopores |
title_full | Electroosmotic Flow Reversal Outside Glass Nanopores |
title_fullStr | Electroosmotic Flow Reversal Outside Glass Nanopores |
title_full_unstemmed | Electroosmotic Flow Reversal Outside Glass Nanopores |
title_short | Electroosmotic Flow Reversal Outside Glass Nanopores |
title_sort | electroosmotic flow reversal outside glass nanopores |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296923/ https://www.ncbi.nlm.nih.gov/pubmed/25490120 http://dx.doi.org/10.1021/nl504237k |
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