Field effect electroosmosis

Ghowsi, Kiumars; Gale, Robert J.

doi:10.1016/0021-9673(91)80061-k

Cited by 66 publications

(53 citation statements)

References 19 publications

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“…The idea of manipulating the ae-potential of a fluidic channel was first formulated by Ghowsi and Gale [90][91][92]. Such voltage bias is supposed to change the ae-potential at wall-solution interface, and therefore can be used to control the current and fluid transport in the channel.…”

Section: Control and Manipulation Of The Wall Potential By An Externamentioning

confidence: 99%

Electrokinetic transport and separations in fluidic nanochannels

et al. 2007

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This article presents a summary of theory, experimental studies, and results for the electrokinetic transport in small fluidic nanochannels. The main focus is on the effect of the electric double layer on the EOF, electric current, and electrophoresis of charged analytes. The double layer thickness can be of the same order as the width of the nanochannels, which has an impact on the transport by shaping the fluid velocity profile, local distributions of the electrolytes, and charged analytes. Our theoretical consideration is limited to continuum analysis where the equations of classical hydrodynamics and electrodynamics still apply. We show that small channels may lead to qualitatively new effects like selective ionic transport based on charge number as well as different modes for molecular separation. These new possibilities together with the rapid development of nanofabrication capabilities lead to an extensive experimental effort to utilize nanochannels for a variety of applications, which are also discussed and analyzed in this review.

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Section: Control and Manipulation Of The Wall Potential By An Externamentioning

confidence: 99%

Electrokinetic transport and separations in fluidic nanochannels

et al. 2007

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“…In the latter case, the ideal geometry of a straight nanochannel is easily realized in experiments, albeit usually with a rectangular cross section. Applications of electrokinetic phenomena in nanochannels include streaming current measurements [19][20][21], electrokinetic energy conversion [8,22,23], ionic [24,25] and flow [26,27] field-effect transistors, electro-osmotic impedance effects [28], and electrophoretic separations [29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Analysis of electrolyte transport through charged nanopores

et al. 2016

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We revisit the classical problem of flow of electrolyte solutions through charged capillary nanopores or nanotubes as described by the capillary pore model (also called "space charge" theory). This theory assumes very long and thin pores and uses a one-dimensional flux-force formalism which relates fluxes (electrical current, salt flux, and fluid velocity) and driving forces (difference in electric potential, salt concentration, and pressure). We analyze the general case with overlapping electric double layers in the pore and a nonzero axial salt concentration gradient. The 3×3 matrix relating these quantities exhibits Onsager symmetry and we report a significant new simplification for the diagonal element relating axial salt flux to the gradient in chemical potential. We prove that Onsager symmetry is preserved under changes of variables, which we illustrate by transformation to a different flux-force matrix given by Gross and Osterle [J. Chem. Phys. 49, 228 (1968)]. The capillary pore model is well suited to describe the nonlinear response of charged membranes or nanofluidic devices for electrokinetic energy conversion and water desalination, as long as the transverse ion profiles remain in local quasiequilibrium. As an example, we evaluate electrical power production from a salt concentration difference by reverse electrodialysis, using an efficiency versus power diagram. We show that since the capillary pore model allows for axial gradients in salt concentration, partial loops in current, salt flux, or fluid flow can develop in the pore. Predictions for macroscopic transport properties using a reduced model, where the potential and concentration are assumed to be invariant with radial coordinate ("uniform potential" or "fine capillary pore" model), are close to results of the full model.

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“…This concept was introduced almost simultaneously by Lee et al [19] and by Ghowsi and Gale [20]. They applied an additional electric field from outside of the capillary.…”

Section: Introductionmentioning

confidence: 97%

“…The external electric field was applied in CZE in several ways, using different media surrounding the outside part of the capillary, e.g., low-conductivity buffer solution [19] or ionized gas [21] or by coating the outer capillary surface by low-conductivity layer of polymeric conductor [22][23][24][25][26] or using metal outer capillary coating [20,27]. By changes of polarity and magnitude of the external electric field, the EOF can be reduced or increased in comparison with the state of absence of the external field, which is in fact equivalent of having a dynamic capillary length.…”

Section: Introductionmentioning

confidence: 99%

Control of EOF in CE by different ways of application of radial electric field

et al. 2007

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Various ways of application of radial electric field for the control of electrokinetic potential and EOF in a home-made device for CE are presented. The device comprises three high-voltage power supplies, which are used to form a radial electric field across the fused-silica capillary wall. One power supply provides the internal electric field - a driving force for electrophoretic migration of charged analytes and for the EOF. Two power supplies are connected to the ends of the outer low-conductivity polymeric coating, which is formed by the dispersion of insoluble conductive copolymer of aniline and p-phenylendiamine in polystyrene matrix (dissolved in N-methylpyrrolidone) attached to the original outer polyimide coating of the capillary. They are able to constitute the external longitudinal electric field with variable values of electric potential at both ends of the outer coating. The potential gradient between the external and internal electric field is perpendicular to the capillary wall and forms a radial electric field across the capillary wall, which affects the electrokinetic potential at the solid-liquid interface and EOF inside the capillary. The developed device and methodology has been applied for the analysis of both chiral and achiral molecules such as terbutaline enantiomers and oligopeptides (diglycine and triglycine). The effect of magnitude, orientation, and different ways of application of the radial electric field on the flow rate of the EOF and on the speed, efficiency, and resolution of CZE separations of the above analytes in the internally noncoated fused-silica capillaries have been evaluated.

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Field effect electroosmosis

Cited by 66 publications

References 19 publications

Electrokinetic transport and separations in fluidic nanochannels

Electrokinetic transport and separations in fluidic nanochannels

Analysis of electrolyte transport through charged nanopores

Control of EOF in CE by different ways of application of radial electric field

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