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Experimental analysis of particle and fluid motion in ac electrokinetics

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Abstract

An ac electric field is applied to induce particle and fluid motion in a wedge-shaped microchannel. Micron-resolution particle image velocimetry (μ-PIV) is used to determine spatially resolved particle velocity and fluid velocity fields. Under steady-state conditions, the particles experience a balance between dielectrophoretic forces induced by the nonuniform electric field and Stokes’ drag forces due to viscous interactions with the fluid. The particle velocity is therefore different from the fluid velocity because of dielectrophoresis. A variant of μ-PIV, two-color μ-PIV, is developed and used to uniquely determine the fluid velocity from the observation of particles without a priori knowledge of the electrical properties. This technique is used to explore ac electrokinetically generated fluid motion. A series of voltage levels at fixed frequency are applied to the wedge-shaped electrodes. The dependency of fluid velocity on applied voltage at different regions in the flow is obtained by fitting power-law curves. This is used to determine the underlying physical phenomena associated with ac electrokinetics. We found that both electrothermal effects and ac electroosmosis are important for the current experimental conditions. However, the electrothermal effect is dominant in the bulk fluid.

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References

  • Adrian RJ (1991) Particle-imaging techniques for experimental fluid mechanics. Ann Rev Fluid Mech 23:261–304

    Google Scholar 

  • Bakewell D, Hughes M, Milner J, Morgan H (1998) Dielectrophoretic manipulation of avidein and DNA. Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society 20(2):1079–1082

    Article  Google Scholar 

  • Brown ABD, Smith CG, Rennie AR (2001) Pumping of water with ac electric fields applied to asymmetric pairs of microelectrodes. Phys Rev E 63, pp 016305/1–8

    Google Scholar 

  • Cummings E (2000) An image processing and optimal nonlinear filtering technique for particle image velocimetry of microflows. Exp Fluids (Suppl) 29(7):42–50

    Google Scholar 

  • Deen W (1998) Analysis of transport phenomena. Oxford University Press, New York

  • Gascoyne PRC, Wang XB, Huang Y, Becker FF (1995) Dielectrophoretic separation of cancer cells from blood. Conference Record of the 1995 IEEE Industry Applications Conference, IEEE, vol 2, pp 1366–73

  • Green N, Ramos A, Gonzalez A, Morgan H, Castellanos A (2000) Fluid flow induced by nonuniform ac electric fields in electrolytes on microelectrodes, I. Experimental measurements. Phys Rev E 61(4):4011–4018

    Article  CAS  Google Scholar 

  • Jones T (1995) Electromechanics of particles. Cambridge University Press, New York

  • Kundu PK, Cohen IM (2002) Fluid Mechanics, 2nd edn. Academic Press, New York

  • Lide DR (2001) CRC Handbook of chemistry and physics, 82nd edn. CRC Press, Boca Raton, FL

  • Meinhart C, Wang D (2001) Accurate measurement of dielectrophoretic (DEP) mobility of particles and macromolecules. Proceedings of μ-TAS 2001, Monterrey, CA, October 21–25, 2001

  • Meinhart C, Wereley S, Santiago J (1999) PIV measurements of a microchannel flow. Exp Fluids 27(5):414–419

    Article  Google Scholar 

  • Meinhart C, Wereley S, Gray M (2000a) Volume illumination for two-dimensional particle image velocimetry. Meas Sci Technol 11(6):809–814

    Article  CAS  Google Scholar 

  • Meinhart C, Wereley S, Santiago J (2000b) A PIV algorithm for estimating time-averaged velocity fields. J Fluids Eng 122(2):285–289

    Article  Google Scholar 

  • Meinhart C, Wang D, Turner K (2003) Measurement of ac electrokinetic flows. Biomed Microdevices 5(2):139–145

    Article  Google Scholar 

  • Morgan H, Green N (2003) AC electrokinetics: colloids and nanoparticles, Research Studies Press Ltd., Baldock, Hertfordshire, England

    Google Scholar 

  • Morgan H, Hughes M, Green N (1999) Separation of submicron bioparticles by dielectrophoresis. Biophys J 77:516–525

    CAS  PubMed  Google Scholar 

  • Olsen MG, Adrian RJ (2000) Out-of-focus effects on particle image visibility and correlation in microscopic particle image velocimetry. Exp Fluids 29 (Suppl S):166–174

    Article  Google Scholar 

  • Prasad AK, Adrian RJ, Landreth CC, Offutt PW (1992) Effect of resolution on the speed and accuracy of particle image velocimetry interrogation. Exp Fluids 13:105–116

    CAS  Google Scholar 

  • Ramos A, Morgan H, Green N, Castellanos A (1998) AC electrokinetics: a review of forces in microelectrode structures. J Phys D Appl Phys 31:2338–2353

    Article  CAS  Google Scholar 

  • Ramos A, Gonzalez A, Green N, 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(4):4019–4028

    Article  Google Scholar 

  • Santiago J, Wereley S, Meinhart C, Beebe D, Adrian R (1998) A particle image velocimetry system for microfluidics. Exp Fluids 25:316–319

    Article  CAS  Google Scholar 

  • Sigurdson M, Meinhart C, Wang D, Liu X, Feng J, Krishnamoorthy S, Makhijani V (2002) Transport enhancement in tunable laser cavity sensor. ASME–IMECE’02 MEMS Symposium, New Orleans, LA, Nov. 17–22, 2002

  • Studeer V, Pepin A, Chen Y, Ajdari A (2002) Fabrication of microfluidic devices for ac electrokinetic fluid pumping. Microelectron Eng (61–62):915–920

  • Wang XB, Vykoukal J, Becker FF, Gascoyne PRC (1998) Separation of polystyrene microbeads using dielectrophoretic/gravitational field-flow-fractionation. Biophys J 74(5):2689–701

    CAS  PubMed  Google Scholar 

  • Wong PK, Chen CY, Wang TH, Ho CM (2003a) An ac electroosmotic processor for biomolecules, TRANSDUCERS ‘03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers. IEEE. vol 1, pp 20–3. Piscataway, NJ, USA

  • Wong PK, Wang JTH, Deval JH, Ho CM (2003b) Electrokinetics in microdevices for biotechnology applications, IEEE/ASME Transactions on Mechatronics

  • Yang J, Huang Y, Wang X, Wang XB, Becker F, Gascoyne PRC (1999a) Dielectric properties of human leukocyte subpopulations determined by electrorotation as a cell separation criterion. Biophys J 76:3307–3314

    CAS  PubMed  Google Scholar 

  • Yang J, Huang Y, Wang XB, Becker F, Gascoyne PRC (1999b) Cell separation on microfabricated electrodes using dielectrophoretic/gravitational field-flow-fractionation. Anal Chem 71(5):911–918

    Article  CAS  PubMed  Google Scholar 

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Acknowledgements

This work is supported by DARPA/ARMY DAAD 19-00-1-0400, DARPA/Air Force F30602-00-2-0609, NSF CTS-9874839 and NSF ACI-0086061.

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Authors and Affiliations

  1. Department of Mechanical & Environmental Engineering, University of California, Santa Barbara, CA, 93106, USA

    Dazhi Wang, Marin Sigurdson & Carl D. Meinhart

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  1. Dazhi Wang
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  2. Marin Sigurdson
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  3. Carl D. Meinhart
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Correspondence to Carl D. Meinhart.

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Wang, D., Sigurdson, M. & Meinhart, C.D. Experimental analysis of particle and fluid motion in ac electrokinetics. Exp Fluids 38, 1–10 (2005). https://doi.org/10.1007/s00348-004-0864-5

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  • DOI: https://doi.org/10.1007/s00348-004-0864-5

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