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Induced-charge electro-osmosis

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dc.contributor.author Squires, Todd M.
dc.contributor.author Bazant, Martin Z.
dc.date.accessioned 2005-08-31T22:33:53Z
dc.date.available 2005-08-31T22:33:53Z
dc.date.issued 2004
dc.identifier.uri http://hdl.handle.net/1721.1/26681
dc.description.abstract We describe the general phenomenon of ‘induced-charge electro-osmosis’ (ICEO) – the nonlinear electro-osmotic slip that occurs when an applied field acts on the ionic charge it induces around a polarizable surface. Motivated by a simple physical picture, we calculate ICEO flows around conducting cylinders in steady (DC), oscillatory (AC), and suddenly applied electric fields. This picture, and these systems, represent perhaps the clearest example of nonlinear electrokinetic phenomena. We complement and verify this physically motivated approach using a matched asymptotic expansion to the electrokinetic equations in the thin-double-layer and low-potential limits. ICEO slip velocities vary as u_s ∝ E_0^2 L, where E_0 is the field strength and L is a geometric length scale, and are set up on a time scale τc =λDL/D, where λD is the screening length and D is the ionic diffusion constant. We propose and analyse ICEO microfluidic pumps and mixers that operate without moving parts under low applied potentials. Similar flows around metallic colloids with fixed total charge have been described in the Russian literature (largely unnoticed in the West). ICEO flows around conductors with fixed potential, on the other hand, have no colloidal analogue and offer further possibilities for microfluidic applications. en
dc.format.extent 533469 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher Cambridge University Press en
dc.rights Copyright: Cambridge University Press This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
dc.subject induced-charge en
dc.subject electro-osmosis en
dc.title Induced-charge electro-osmosis en
dc.identifier.citation Journal of Fluid Mechanics 509, p.217-252 (2004) en


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