Frequency-Dependent Electroosmosis

Reppert, Philip M.; Morgan, Frank Dale

doi:10.1006/jcis.2002.8596

Cited by 51 publications

(49 citation statements)

References 15 publications

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“…This induces steady motion of the liquid, a flow termed ac electro-osmosis because of its similarity to electroosmosis in a dc field [5][6][7][8]. It should be emphasized that the ac electro-osmotic flow observed over microelectrodes differs from ac electro-osmosis observed in capillaries [9]. In the latter case, the electric field is uniform along the capillary but time-varying.…”

Section: Introductionmentioning

confidence: 99%

Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

Castellanos

Ramos

González-Weller

et al. 2003

J. Phys. D: Appl. Phys.

615

682

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The movement and behaviour of particles suspended in aqueous solutions subjected to non-uniform ac electric fields is examined. The ac electric fields induce movement of polarizable particles, a phenomenon known as dielectrophoresis. The high strength electric fields that are often used in separation systems can give rise to fluid motion, which in turn results in a viscous drag on the particle. The electric field generates heat, leading to volume forces in the liquid. Gradients in conductivity and permittivity give rise to electrothermal forces and gradients in mass density to buoyancy. In addition, non-uniform ac electric fields produce forces on the induced charges in the diffuse double layer on the electrodes. This causes a steady fluid motion termed ac electro-osmosis. The effects of Brownian motion are also discussed in this context. The orders of magnitude of the various forces experienced by a particle in a model microelectrode system are estimated. The results are discussed in relation to experiments and the relative influence of each type of force is described.

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Section: Introductionmentioning

confidence: 99%

Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

Castellanos

Ramos

González-Weller

et al. 2003

J. Phys. D: Appl. Phys.

615

682

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“…Seismoelectric and electroseismic measurements made on Earth's surface or in a borehole may provide information about the subsurface properties (Mikhailov et al (1997); Zhu and Toksöz (2005)). Electroseismic laboratory experiments (Zhu et al (1994(Zhu et al ( , 1999; Reppert and Morgan (2002)) with scaled layered and borehole models showed that electroseismic waves are induced with electrodes buried in a fluid-saturated formation or in a borehole. Deckman et al (2005) determined the electroseismic coupling coefficients with a simple measurement cell in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

Electroseismic and seismoelectric measurements of rock samples in a water tank

Zhu¹,

Burns²,

Toksöz³

2007

SEG Technical Program Expanded Abstracts 2007

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An electromagnetic wave or a seismic wave can induce seismic or electric waves due to the electrokinetic conversion based on the electric double layer in a fluidsaturated porous medium. In this paper, we observe the acoustic fields generated around the electrodes excited by an electric pulse in a water tank. The electroseismic or seismoelectric waves are measured in the water tank system to confirm that the recorded seismic or electric signals are induced in porous samples due to the electrokinetic conversions. The electroseismic and seismoelectric frequency-responses in Berea sandstone and Westerly granite samples are measured at frequency range of 15 kHz to 150 kHz. The experimental measurements show that the effects of the electric source, background noises, and electroseismic or seismoelectric conversions are separated very clearly. We calculate the electroseismic and seismoelectric normalized coupling coefficients in the rock samples and compare them with the theoretical calculation. The variation trends of the normalized coupling coefficients are in agreement with the theoretical predictions. The measurement method in this paper could be used to investigate other electroseismic and seismoelectric properties for petroleum exploration applications.

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“…It involves the interaction of ions in the fluid with the solid surface, and their dynamics under an applied electric field tangential to the fluid-solid interface. The EK effect includes four main topics: electroosmosis (EO), streaming potential (SP), electrophoresis, and sedimentation potential [2][3][4][5]. In the past two decades, the EK effect has experienced a strong revival mainly owing to its various potential applications, e.g., an EO pump with no moving parts that can propel electrolytes and particles in the microscale [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], as well as manipulate biological cells [24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Self-Consistent Approach to Global Charge Neutrality in Electrokinetics: A Surface Potential Trap Model

Wan

Liao

et al. 2014

Phys. Rev. X

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In this work, we treat the Poisson-Nernst-Planck (PNP) equations as the basis for a consistent framework of the electrokinetic effects. The static limit of the PNP equations is shown to be the charge-conserving Poisson-Boltzmann (CCPB) equation, with guaranteed charge neutrality within the computational domain. We propose a surface potential trap model that attributes an energy cost to the interfacial charge dissociation. In conjunction with the CCPB, the surface potential trap can cause a surface-specific adsorbed charge layer σ. By defining a chemical potential μ that arises from the charge neutrality constraint, a reformulated CCPB can be reduced to the form of the Poisson-Boltzmann equation, whose prediction of the Debye screening layer profile is in excellent agreement with that of the Poisson-Boltzmann equation when the channel width is much larger than the Debye length. However, important differences emerge when the channel width is small, so the Debye screening layers from the opposite sides of the channel overlap with each other. In particular, the theory automatically yields a variation of σ that is generally known as the "charge regulation" behavior, attendant with predictions of force variation as a function of nanoscale separation between two charged surfaces that are in good agreement with the experiments, with no adjustable or additional parameters. We give a generalized definition of the ζ potential that reflects the strength of the electrokinetic effect; its variations with the concentration of surface-specific and surfacenonspecific salt ions are shown to be in good agreement with the experiments. To delineate the behavior of the electro-osmotic (EO) effect, the coupled PNP and Navier-Stokes equations are solved numerically under an applied electric field tangential to the fluid-solid interface. The EO effect is shown to exhibit an intrinsic time dependence that is noninertial in its origin. Under a step-function applied electric field, a pulse of fluid flow is followed by relaxation to a new ion distribution, owing to the diffusive counter current. We have numerically evaluated the Onsager coefficients associated with the EO effect, L 21 , and its reverse streaming potential effect, L 12 , and show that L 12 ¼ L 21 in accordance with the Onsager relation. We conclude by noting some of the challenges ahead.

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Frequency-Dependent Electroosmosis

Cited by 51 publications

References 15 publications

Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

Electroseismic and seismoelectric measurements of rock samples in a water tank

Self-Consistent Approach to Global Charge Neutrality in Electrokinetics: A Surface Potential Trap Model

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