Induced-charge electro-osmosis
Name
Bazant_2004_Induced.pdf
Size
520.97 KB
Format
Adobe PDF
Checksum (MD5)
60752c42e76aff105e570ab2d6c2f94c
Author(s)
Squires, Todd M.
Bazant, Martin Z.
Date Issued
2004
Publisher
Cambridge University Press
Citation
Journal of Fluid Mechanics 509, p.217-252 (2004)
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.
Subjects
induced-charge
electro-osmosis
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Terms of Use
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.
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.
Persistent DSpace Link
