Effects of electrostatic correlations on electrokinetic phenomena
The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2013
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| Online Access: | http://hdl.handle.net/1721.1/77132 |
| _version_ | 1811076643729440768 |
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| author | Storey, Brian D. Bazant, Martin Z. |
| author2 | Massachusetts Institute of Technology. Department of Chemical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Chemical Engineering Storey, Brian D. Bazant, Martin Z. |
| author_sort | Storey, Brian D. |
| collection | MIT |
| description | The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for nonlocal electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture subtle aspects of molecular simulations and allows for simple calculations of electrokinetic flows in correlated ionic fluids. Charge-density oscillations tend to reduce electro-osmotic flow and streaming current, and overscreening of surface charge can lead to flow reversal. These effects also help to explain the suppression of induced-charge electrokinetic phenomena at high salt concentrations. |
| first_indexed | 2024-09-23T10:25:21Z |
| format | Article |
| id | mit-1721.1/77132 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:25:21Z |
| publishDate | 2013 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/771322022-09-30T20:58:53Z Effects of electrostatic correlations on electrokinetic phenomena Storey, Brian D. Bazant, Martin Z. Massachusetts Institute of Technology. Department of Chemical Engineering Massachusetts Institute of Technology. Department of Mathematics Bazant, Martin Z. The classical theory of electrokinetic phenomena is based on the mean-field approximation that the electric field acting on an individual ion is self-consistently determined by the local mean charge density. This paper considers situations, such as concentrated electrolytes, multivalent electrolytes, or solvent-free ionic liquids, where the mean-field approximation breaks down. A fourth-order modified Poisson equation is developed that captures the essential features in a simple continuum framework. The model is derived as a gradient approximation for nonlocal electrostatics of interacting effective charges, where the permittivity becomes a differential operator, scaled by a correlation length. The theory is able to capture subtle aspects of molecular simulations and allows for simple calculations of electrokinetic flows in correlated ionic fluids. Charge-density oscillations tend to reduce electro-osmotic flow and streaming current, and overscreening of surface charge can lead to flow reversal. These effects also help to explain the suppression of induced-charge electrokinetic phenomena at high salt concentrations. National Science Foundation (U.S.). (Contracts DMS-0707641) 2013-02-15T14:42:34Z 2013-02-15T14:42:34Z 2012-11 2012-09 Article http://purl.org/eprint/type/JournalArticle 1539-3755 1550-2376 http://hdl.handle.net/1721.1/77132 Storey, Brian D., and Martin Z. Bazant. “Effects of Electrostatic Correlations on Electrokinetic Phenomena.” Physical Review E 86.5 (2012). ©2012 American Physical Society en_US http://dx.doi.org/10.1103/PhysRevE.86.056303 Physical Review E Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Storey, Brian D. Bazant, Martin Z. Effects of electrostatic correlations on electrokinetic phenomena |
| title | Effects of electrostatic correlations on electrokinetic phenomena |
| title_full | Effects of electrostatic correlations on electrokinetic phenomena |
| title_fullStr | Effects of electrostatic correlations on electrokinetic phenomena |
| title_full_unstemmed | Effects of electrostatic correlations on electrokinetic phenomena |
| title_short | Effects of electrostatic correlations on electrokinetic phenomena |
| title_sort | effects of electrostatic correlations on electrokinetic phenomena |
| url | http://hdl.handle.net/1721.1/77132 |
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