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Macro-scale description of transient electro-kinetic phenomena over polarizable dielectric solids

Published online by Cambridge University Press:  10 February 2009

G. YOSSIFON
Affiliation:
School of Mechanical Engineering, University of Tel-Aviv, Tel-Aviv 69978, Israel
I. FRANKEL
Affiliation:
Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
T. MILOH*
Affiliation:
School of Mechanical Engineering, University of Tel-Aviv, Tel-Aviv 69978, Israel
*
Email address for correspondence: [email protected]

Abstract

We have studied the temporal evolution of electro-kinetic flows in the vicinity of polarizable dielectric solids following the application of a ‘weak’ transient electric field. To obtain a macro-scale description in the limit of narrow electric double layers (EDLs), we have derived a pair of effective transient boundary conditions directly connecting the electric potentials across the EDL. Within the framework of the above assumptions, these conditions apply to a general transient electro-kinetic problem involving dielectric solids of arbitrary geometry and relative permittivity. Furthermore, the newly derived scheme is applicable to general transient and spatially non-uniform external fields. We examine the details of the physical mechanisms involved in the relaxation of the induced-charging process of the EDL adjacent to polarizable dielectric solids. It is thus established that the time scale characterizing the electrostatic relaxation increases with the dielectric constant of the solid from the Debye time (for the diffusion across the EDL) through the ‘intermediate’ scale (proportional to the product of the respective Debye- and geometric-length scales). Thus, the present rigorous analysis substantiates earlier results largely obtained by heuristic use of equivalent RC-circuit models. Furthermore, for typical values of ionic diffusivity and kinematic viscosity of the electrolyte solution, the latter time scale is comparable to the time scale of viscous relaxation in problems concerning microfluidic applications or micro-particle dynamics. The analysis is illustrated for spherical micro-particles. Explicit results are thus presented for the temporal evolution of electro-osmosis around a dielectric sphere immersed in unbounded electrolyte solution under the action of a suddenly applied uniform field, combining both induced charge and ‘equilibrium’ (fixed charge) contributions to the zeta potential. It is demonstrated that, owing to the time delay of the induced-EDL charging, the ‘equilibrium’ contribution to fluid motion (which is linear in the electric field) initially dominates the (quadratic) ‘induced’ contribution.

Type
Papers
Copyright
Copyright © Cambridge University Press 2009

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References

REFERENCES

Ajdari, A. 2000 Pumping liquids using asymmetric electrode arrays. Phys. Rev. E 61, 4548.Google ScholarPubMed
Arlt, G., Hennings, D. & de With, G. 1985 Dielectric properties of fine-grained barium titanate ceramics. J. Appl. Phys. 58, 16191625.CrossRefGoogle Scholar
Bazant, M. Z. & Squires, T. M. 2004 Induced-charge electro-kinetic phenomena: theory and microfluidic applications. Phys. Rev. Lett. 92, 066101-1-4.CrossRefGoogle Scholar
Bazant, M. Z., Thornton, K. & Ajdari, A. 2004 Diffuse-charge dynamics in electrochemical systems. Phys. Rev. E 70, 021506–24.Google ScholarPubMed
Brown, A. B. D., Smith, C. G. & Rennie, A. R. 2002 Pumping of water with AC electricfields applied to asymmetric pairs of microelectrodes. Phys. Rev. E 63, 016305–8.Google Scholar
Campisi, M., Accoto, D. & Dario, P. 2005 AC electroosmosis in rectangular microchannels. J. Chem. Phys. 123, 204724–9.CrossRefGoogle ScholarPubMed
Chu, K. T. & Bazant, M. Z. 2006 Nonlinear electrochemical relaxation around conductors. Phys. Rev. E 74, 011501–25.Google ScholarPubMed
Dose, E. V. & Guiochon, G. 1993 Timescales of transient processes in capillary electrophoresis. J. Chromatogr. A 652, 263275.CrossRefGoogle Scholar
Dukhin, A. S. 1986 Pair interaction of disperse particles in electric-field. 3. Hydrodynamic interaction of ideally polarizable metal particles and dead biological cells. Colloid J. USSR 48, 376381.Google Scholar
Dukhin, A. S. & Murtsovkin, V. A. 1986 Pair interaction of particles in electric-field. 2. Influence of polarization of double-layer of dielectric particles on their hydrodynamic interaction in a stationary electric-field. Colloid J. USSR 48, 203209.Google Scholar
Erickson, D. & Li, D. 2003 Analysis of alternating current electroosmotic flows in a rectangular microchannel. Langmuir 19, 54215430.CrossRefGoogle Scholar
Fan, Z. H. & Harrison, D. J. 1994 Micromachining of capillary electrophoresis injectors and separators on glass chips and evaluation of flow at capillary intersections. Anal. Chem. 66, 177184.CrossRefGoogle Scholar
Flores-Rodriguez, N. F. & Markx, G. H. 2006 Anomalous dielectrophoretic behaviour of barium titanate microparticles in concentrated solutions of ampholytes. J. Phys. D 39, 33563361.Google Scholar
Gamayunov, N. I., Murtsovkin, V. A. & Dukhin, A. S. 1986 Pair interaction of particles in electric-field. 1. Features of hydrodynamic interaction of polarized particles. Colloid J. USSR 48, 197203.Google Scholar
Gonzalez, A., Ramos, A., Green, N. G., Castellanos, A. & Morgan, H. 2000 Fluid flow induced by nonuniform AC electric fields in electrolytes on microelectrodes. II. A linear double-layer analysis. Phys. Rev. E 61, 40194028.Google Scholar
Hanna, W. T. & Osterle, J. F. 1968 Transient electro-osmosis in capillary tubes. J. Chem. Phys. 49, 40624068.CrossRefGoogle Scholar
Happel, J. & Brenner, H. 1965 Low Reynolds Number Hydrodynamics. Prentice-Hall.Google Scholar
Harnett, C. K., Templeton, J., Dunphy-Guzman, K. A., Senousya, Y. M. & Kanouff, M. P. 2008 Model based design of a microfluidic mixer driven by induced charge electroosmosis. Lab Chip. 8, 565572.CrossRefGoogle ScholarPubMed
Ivory, C. F. 1983 Transient electroosmosis: the momentum transfer coefficient. J. Colloid Interface Sci. 96, 296298.CrossRefGoogle Scholar
Ivory, C. F. 1984 Transient electrophoresis of a dielectric sphere. J. Colloid Interface Sci. 100, 239249.CrossRefGoogle Scholar
Jacobson, S. C., Culbertson, C. T., Daler, J. E. & Ramsey, J. M. 1998 Microchip structures for submillisecond electrophoresis. Anal. Chem. 70, 34763480.CrossRefGoogle Scholar
Jacobson, S. C., Hergenroder, R., Koutny, L. B. & Ramsey, J. M. 1994 High-speed separations on a microchip. Anal. Chem. 66, 11141118.CrossRefGoogle Scholar
Kang, Y., Yang, C. & Huang, X. 2002 Dynamic aspects of electroosmotic flow in a cylindrical Microcapillary. Int. J. Engng Sci. 40, 22032221.CrossRefGoogle Scholar
Keh, H. J. & Huang, Y. C. 2005 Transient electrophoresis of dielectric spheres. J. Colloid Interface Sci. 291, 282291.CrossRefGoogle ScholarPubMed
Keh, H. J. & Tseng, H. C. 2001 Transient electro-kinetic flow in fine capillaries. J. Colloid Interface Sci. 242, 450459.CrossRefGoogle Scholar
Kuo, D. H., Chang, C. C., Su, T. Y., Wang, W. K. & Lin, B. Y. 2004 Dielectric properties of three ceramic/epoxy composites. Mater. Chem. Phys. 85, 201206.CrossRefGoogle Scholar
Levich, V. G. 1962 Physicochemical Hydrodynamics. Prentice-Hall.Google Scholar
Lide, D. R. 1994 CRC Handbook of Chemistry and Physics, 74th ed.CRC Press.Google Scholar
Luo, W. J. 2004 Transient electroosmotic flow induced by DC or AC electric fields in a curved microtube. J. Colloid Interface Sci. 278, 497507.CrossRefGoogle ScholarPubMed
Lyklema, J. 1995 Fundamentals of Interface and Colloid Science. Vol. II. Solid–liquid Interfaces. Academic Press.Google Scholar
Macdonald, J. R. 1970 Double layer capacitance and relaxation in electrolytes and solids. Trans. Faraday Soc. 66, 943958.CrossRefGoogle Scholar
Miloh, T. 2008 a Dipolophoresis of nanoparticles. Phys. Fluids 20, 063303–12.CrossRefGoogle Scholar
Miloh, T. 2008 b A unified theory for dipolophoresis of nanoparticles. Phys. Fluids. 20, 107105–14.CrossRefGoogle Scholar
Mishchuk, N. A. & Gonzalez, C. F. 2006 Nonstationary electroosmotic flow in open cylindrical capillaries. Electrophoresis 27, 650660.CrossRefGoogle ScholarPubMed
Morrison, F. A. 1969 Transient electrophoresis of a dielectric sphere. J. Colloid Interface Sci. 29, 687691.CrossRefGoogle Scholar
Morrison, F. A. 1971 Transient electrophoresis of an arbitrarily oriented cylinder. J. Colloid Interface Sci. 36, 139143.CrossRefGoogle Scholar
Murtsovkin, V. A. 1996 Nonlinear flows near polarized disperse particles. Colloid J. 58, 341349.Google Scholar
Nadal, F., Argoul, F., Kestener, P., Pouligny, B., Ybert, C. & Ajdari, A. 2002 Electrically induced flows in the vicinity of a dielectric stripe on a conducting plane. Eur. Phys. J. E 9, 387399.Google ScholarPubMed
Ramos, A., Morgan, H., Green, N. G. & Castellanos, A. 1999 AC electric-field- induced fluid flow in microelectrodes. J. Colloid Interface Sci. 217, 420422.CrossRefGoogle ScholarPubMed
Santiago, J. G. 2001 Electroosmotic flows in microchannels with finite inertial and pressure forces. Anal. Chem. 73, 23532365.CrossRefGoogle ScholarPubMed
Simonov, I. N. & Dukhin, S. S. 1973 Theory of electrophoresis of solid conducting particles in case of ideal polarization of a thin diffuse double-layer. Colloid J. 35, 173176.Google Scholar
Simonov, I. N. & Shilov, V. N. 1973 Theory of the polarization of the diffuse part of a thin double layer at conducting, spherical particles in an alternating electric field. Colloid J. 35, 350353.Google Scholar
Soderman, O. & Jonsson, B. 1996 Electro-osmosis: velocity profiles in different geometries with both temporal and spatial resolution. J. Chem. Phys. 105, 1030010311.CrossRefGoogle Scholar
Squires, T. M. & Bazant, M. Z. 2004 Induced-charge electro-osmosis. J. Fluid Mech. 509, 217252.CrossRefGoogle Scholar
Takhistov, P., Duginova, K. & Chang, H. C. 2003 Electro-Kinetic mixing due to electrolyte depletion at microchannel junction. J. Colloid Interface Sci. 263, 133143.CrossRefGoogle Scholar
Thamida, S. K. & Chang, H. C. 2002 Nonlinear electro-kinetic ejection and entrainment due to polarization at nearly insulated wedges. Phys. Fluids. 14, 43154328.CrossRefGoogle Scholar
Wang, S. C., Chena, H. P., Lee, C. Y., Yu, C. C., & Chang, H. C. 2006 AC electroosmotic mixing induced by non-contact external electrodes. Biosens. Bioelectr. 22, 563567.CrossRefGoogle ScholarPubMed
Yan, D., Yang, C., Nguyen, N. T. & Huang, X. 2007 Diagnosis of transient electro-kinetic flow in microfluidic channels. Phys. Fluids 19, 017114–10.CrossRefGoogle Scholar
Yang, C., Ng, C. B. & Chan, V. 2002 Transient analysis of electroosmotic flow in a slit microchannel. J. Colloid Interface Sci. 248, 524527.CrossRefGoogle Scholar
Yang, M. C., Ooi, K. T., Wong, T. N. & Masliyah, J. H. 2004 Frequency dependent laminar electroosmotic flow in a closed - end rectangular microchannel. J. Colloid Interface Sci. 275, 679698.Google Scholar
Yariv, E. 2008 Slender-body approximations for electro-phoresis and electro-rotation of polarizable particles. J. Fluid Mech. 613, 8594.CrossRefGoogle Scholar
Yossifon, G., Frankel, I. & Miloh, T. 2006 On electro-osmotic flows through micro channel junctions. Phys. Fluids. 18, 117108–9.CrossRefGoogle Scholar
Yossifon, G., Frankel, I. & Miloh, T. 2007 Symmetry breaking in induced-charge electroosmosis over polarizable spheroids. Phys. Fluids 19, 068105–4.CrossRefGoogle Scholar
Zhang, Y., Wong, T. N., Yang, C. & Ooi, K. T. 2006 Dynamic aspects of electroosmotic flow. Microfluid Nanofluid 2, 205214.CrossRefGoogle Scholar