Induced-charge electrophoresis near a wall
Induced-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls in real systems further break symmetry and lead to dielectrophoresis (DEP) in local field gradients. Zhao and Bau (Langmuir 2007, 23, 4053) predicted that a metal (ideally...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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WILEY-VCH Verlag GmbH & Co.
2011
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| Online Access: | http://hdl.handle.net/1721.1/62810 |
| _version_ | 1826199842213330944 |
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| author | Kilic, Mustafa Sabri Bazant, Martin Z. |
| author2 | Massachusetts Institute of Technology. Department of Chemical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Chemical Engineering Kilic, Mustafa Sabri Bazant, Martin Z. |
| author_sort | Kilic, Mustafa Sabri |
| collection | MIT |
| description | Induced-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls in real systems further break symmetry and lead to dielectrophoresis (DEP) in local field gradients. Zhao and Bau (Langmuir 2007, 23, 4053) predicted that a metal (ideally polarizable) cylinder is repelled from an insulating wall in a DC field. We revisit this problem with an AC field and show that attraction to the wall sets in at high frequency and leads to an equilibrium distance, where DEP balances ICEP, although, in three dimensions, a metal sphere is repelled from the wall at all frequencies. This conclusion, however, does not apply to asymmetric particles. Consistent with the experiments of Gangwal et al. (Phys. Rev. Lett. 2008, 100, 058302), we show that a metal/insulator Janus particle is always attracted to the wall in an AC field. The Janus particle tends to move toward its insulating end, perpendicular to the field, but ICEP torque rotates this end toward the wall. Under some conditions, the theory predicts steady translation along the wall, perpendicular to the field, at an equilibrium tilt angle around 45°, consistent with the experiments, although improved models are needed for a complete understanding of this phenomenon. |
| first_indexed | 2024-09-23T11:26:38Z |
| format | Article |
| id | mit-1721.1/62810 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:26:38Z |
| publishDate | 2011 |
| publisher | WILEY-VCH Verlag GmbH & Co. |
| record_format | dspace |
| spelling | mit-1721.1/628102022-09-27T19:34:01Z Induced-charge electrophoresis near a wall Kilic, Mustafa Sabri Bazant, Martin Z. Massachusetts Institute of Technology. Department of Chemical Engineering Massachusetts Institute of Technology. Department of Mathematics Bazant, Martin Z. Bazant, Martin Z. Kilic, Mustafa Sabri Induced-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls in real systems further break symmetry and lead to dielectrophoresis (DEP) in local field gradients. Zhao and Bau (Langmuir 2007, 23, 4053) predicted that a metal (ideally polarizable) cylinder is repelled from an insulating wall in a DC field. We revisit this problem with an AC field and show that attraction to the wall sets in at high frequency and leads to an equilibrium distance, where DEP balances ICEP, although, in three dimensions, a metal sphere is repelled from the wall at all frequencies. This conclusion, however, does not apply to asymmetric particles. Consistent with the experiments of Gangwal et al. (Phys. Rev. Lett. 2008, 100, 058302), we show that a metal/insulator Janus particle is always attracted to the wall in an AC field. The Janus particle tends to move toward its insulating end, perpendicular to the field, but ICEP torque rotates this end toward the wall. Under some conditions, the theory predicts steady translation along the wall, perpendicular to the field, at an equilibrium tilt angle around 45°, consistent with the experiments, although improved models are needed for a complete understanding of this phenomenon. National Science Foundation (U.S.) (Contract No. DMS-0707641) Ecole supérieure de physique et de chimie (Paris, France) 2011-05-10T20:42:13Z 2011-05-10T20:42:13Z 2011-02 Article http://purl.org/eprint/type/JournalArticle 0173-0835 1522-2683 http://hdl.handle.net/1721.1/62810 Kilic, Mustafa Sabri, and Martin Z. Bazant. “Induced-charge Electrophoresis Near a Wall.” Electrophoresis 32.5 (2011) : 614-628. en_US http://dx.doi.org/10.1002/elps.201000481 Electrophoresis Creative Commons Attribution-Noncommercial-Share Alike 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ application/pdf WILEY-VCH Verlag GmbH & Co. MIT web domain |
| spellingShingle | Kilic, Mustafa Sabri Bazant, Martin Z. Induced-charge electrophoresis near a wall |
| title | Induced-charge electrophoresis near a wall |
| title_full | Induced-charge electrophoresis near a wall |
| title_fullStr | Induced-charge electrophoresis near a wall |
| title_full_unstemmed | Induced-charge electrophoresis near a wall |
| title_short | Induced-charge electrophoresis near a wall |
| title_sort | induced charge electrophoresis near a wall |
| url | http://hdl.handle.net/1721.1/62810 |
| work_keys_str_mv | AT kilicmustafasabri inducedchargeelectrophoresisnearawall AT bazantmartinz inducedchargeelectrophoresisnearawall |