Induced-charge electro-osmotic flow around cylinders with various orientations

Canpolat, Çetin

doi:10.1177/0954406216656886

Cited by 12 publications

(4 citation statements)

References 26 publications

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“…To this end, we present a numerical simulation study of active control on the transient growth of the ion depletion layer by driving ICEK streaming flows in present study, which resolves well the aforementioned defects for on‐chip nanofluidics‐based macromolecule sensing. In fact, the idea was originally proposed by Park and Yossifon .…”

Section: Introductionmentioning

confidence: 69%

On ion transport regulation with field‐effect nonlinear electroosmosis control in microfluidics embedding an ion‐selective medium

et al. 2020

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On ion transport regulation with field-effect nonlinear electroosmosis control in microfluidics embedding an ion-selective mediumWe study herein numerically the use of induced-charge electrokinetic phenomena to enable a flexible control of ion transport of dilute electrolyte in a straight ion concentration polarization system. The effect of three convection modes of induced-charge electrokinetic phenomena, including induced-charge electroosmosis, flow-field effect transistor, and alternating-current electroosmosis (ACEO), on convective arrestment of diffusive wave-front propagation is investigated by developing a cross-scale and fully coupled transient numerical simulation model, wherein multiple frequency electrochemical polarization and nonlinear diffuse charge dynamics in spatiotemporally varying solution conductivity are taken into account. We demonstrate by detailed comparative simulation studies that ACEO vortex flow field above a metal strip array arranged along the anodic chamber's bottom surface serves as the most efficient way for adjusting the salt density distribution at micrometer and even millimeter dimension, due to its high flexibility in controlling the stirring flow state with the introduction of two extra electrical parameters. The specific operating status is determined by whether the electrode array is floating in potential (induced-charge electroosmosis) or biased to ground (flow-field effect transistor) or forced to oscillate at another Fourier mode (ACEO). These results prove useful for on-chip electric current control with electroconvective stirring.

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Section: Introductionmentioning

confidence: 69%

On ion transport regulation with field‐effect nonlinear electroosmosis control in microfluidics embedding an ion‐selective medium

et al. 2020

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“…Besides the native EDL full of cations within the dielectric nanopore, the conducting nanochannel mounted at the pore entrance can be readily polarized by a DC electric field imposed along the channel length direction, which gives rise to additional induced counterions of a bipolar nature under the covering region of the metal pore via the physical principle of induced-charge electrokinetics (ICEK) (Figure 2b,c) [65][66][67][68][69][70][71][72][73]. Namely, more cations than anions are induced on the anodic side of the conducting wall, while excessive anions are induced on the cathodic side of the conducting channel, regardless of the specific polarity of the applied DC bias (Figure 2b,c).…”

Section: Chip Geometry and Device Operation Principlementioning

confidence: 99%

A Simulation Analysis of Nanofluidic Ion Current Rectification Using a Metal-Dielectric Janus Nanopore Driven by Induced-Charge Electrokinetic Phenomena

et al. 2020

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We propose herein a unique mechanism of generating tunable surface charges in a metal-dielectric Janus nanopore for the development of nanofluidic ion diode, wherein an uncharged metallic nanochannel is in serial connection with a dielectric nanopore of fixed surface charge. In response to an external electric field supplied by two probes located on both sides of the asymmetric Janus nanopore, the metallic portion of the nanochannel is electrochemically polarized, so that a critical junction is formed between regions with an enriched concentration of positive and negative ions in the bulk electrolyte adjacent to the conducting wall. The combined action of the field-induced bipolar induced double layer and the native unipolar double layer full of cations within the negatively-charged dielectric nanopore leads to a voltage-controllable heterogenous volumetric charge distribution. The electrochemical transport of field-induced counterions along the nanopore length direction creates an internal zone of ion enrichment/depletion, and thereby enhancement/suppression of the resulting electric current inside the Janus nanopore for reverse working status of the nanofluidic ion diode. A mathematical model based upon continuum mechanics is established to study the feasibility of the Janus nanochannel in causing sufficient ion current rectification, and we find that only a good matching between pore diameter and Debye length is able to result in a reliable rectifying functionality for practical applications. This rectification effect is reminiscent of the typical bipolar membrane, but much more flexible on account of the nature of a voltage-based control due to induced-charge electrokinetic polarization of the conducting end, which may hold promise for osmotic energy conversion wherein an electric current appears due to a difference in salt concentration. Our theoretical demonstration of a composite metal-dielectric ion-selective medium provides useful guidelines for construction of flexible on-chip platforms utilizing induced-charge electrokinetic phenomena for a high degree of freedom ion current control.

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“…Because the ionic charge layer emerges as a result of the applied AC electric field, both the induced free charge and tangential field component are sinusoidal functions of the time variable under Debye-Huckel limit, resulting in time-averaged electroosmosis flow even in a harmonically oscillating field [ 23 , 24 , 25 ]. Later, Bazant and Squires [ 26 , 27 ] indicated that a background electric field can act on its own induced free charge within the Debye layer at a polarizable phase interface, which is genuinely a more accurate physical description of nonlinear electrokinetic phenomena, and they coined the term ‘Induced-Charge Electroosmosis (ICEO)’ to delineate electroosmotic streaming on polarizable or highly-charged solid surfaces immersed in saline solutions, which has incorporated the physical concepts of AC electroosmosis/traveling-wave electroosmosis (ACEO/TWEO) on driving electrodes in standing-wave [ 28 , 29 ]/traveling-wave [ 30 , 31 , 32 , 33 , 34 , 35 ] electric fields, ICEO on bipolar conducting [ 15 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]/semiconducting [ 43 , 44 ]/dielectric [ 16 , 45 , 46 , 47 , 48 ] materials, and electroosmosis of second kind due to surface-conduction-induced bulk concentration polarization [ 49 , 50 , 51 , 52 ]. This new category of electrohydrodynamic flow shows great advantages in suppressing electrode reactions and bubble productions, as well as actuating faster fluid flows than conventional linear electroosmosis, by virtue of its second-order voltage dependence in time-varying electric fields [ 14 , 53 , 54 ,…”

Section: Introductionmentioning

confidence: 99%

On AC-Field-Induced Nonlinear Electroosmosis next to the Sharp Corner-Field-Singularity of Leaky Dielectric Blocks and Its Application in on-Chip Micro-Mixing

et al. 2018

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Induced-charge electroosmosis has attracted lots of attention from the microfluidic community over the past decade. Most previous researches on this subject focused on induced-charge electroosmosis (ICEO) vortex streaming actuated on ideally polarizable surfaces immersed in electrolyte solutions. Starting from this point, we conduct herein a linear asymptotic analysis on nonlinear electroosmotic flow next to leaky dielectric blocks of arbitrary electrical conductivity and dielectric permittivity in harmonic AC electric fields, and theoretically demonstrate that observable ICEO fluid motion can be generated at high field frequencies in the vicinity of nearly insulating semiconductors, a very low electrical conductivity, of which can evidently increase the double-layer relaxation frequency (inversely proportional to the solid permittivity) to be much higher than the typical reciprocal RC time constant for induced double-layer charging on ideally polarizable surfaces. A computational model is developed to study the feasibility of this high-frequency vortex flow field of ICEO for sample mixing in microfluidics, in which the usage of AC voltage signal at high field frequencies may be beneficial to suppress electrochemical reactions to some extent. The influence of various parameters for developing an efficient mixer is investigated, and an integrated arrangement of semiconductor block array is suggested for achieving a reliable mixing performance at relatively high sample fluxes. Our physical demonstration with high-frequency ICEO next to leaky dielectric blocks using a simple channel structure offers valuable insights into the design of high-throughput micromixers for a variety of lab-on-a-chip applications.

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Induced-charge electro-osmotic flow around cylinders with various orientations

Cited by 12 publications

References 26 publications

On ion transport regulation with field‐effect nonlinear electroosmosis control in microfluidics embedding an ion‐selective medium

On ion transport regulation with field‐effect nonlinear electroosmosis control in microfluidics embedding an ion‐selective medium

A Simulation Analysis of Nanofluidic Ion Current Rectification Using a Metal-Dielectric Janus Nanopore Driven by Induced-Charge Electrokinetic Phenomena

On AC-Field-Induced Nonlinear Electroosmosis next to the Sharp Corner-Field-Singularity of Leaky Dielectric Blocks and Its Application in on-Chip Micro-Mixing

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