On controlling the flow behavior driven by induction electrohydrodynamics in microfluidic channels

Abstract

In this study, we develop a nondimensional physical model to demonstrate fluid flow at the micrometer dimension driven by traveling-wave induction electrohydrodynamics (EHD) through direct numerical simulation. In order to realize an enhancement in the pump flow rate as well as a flexible adjustment of anisotropy of flow behavior generated by induction EHD in microchannels, while not adding the risk of causing dielectric breakdown of working solution and material for insulation, a pair of synchronized traveling-wave voltage signals are imposed on double-sided electrode arrays that are mounted on the top and bottom insulating substrate, respectively. Accordingly, we present a model evidence, that not only the pump performance is improved evidently, but a variety of flow profiles, including the symmetrical and parabolic curve, plug-like shape and even biased flow behavior of quite high anisotropy are produced by the device design of "mix-type", "superimposition-type" and "adjustable-type" proposed herein as well, with the resulting controllable fluid motion being able to greatly facilitate an on-demand transportation mode of on-chip bio-microfluidic samples. Besides, automatic conversion in the direction of pump flow is achievable by switching on and off a second voltage wave. Our results provide utilitarian guidelines for constructing flexible electrokinetic framework useful in controllable transportation of particle and fluid samples in modern microfluidic systems.

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

“…The tilde symbol ~ is dropped henceforward for convenience of expression. Within the liquid solution and leaky dielectric blocks, charge conservation in sinusoidal state is given by Equations (3) and (4), respectively [ 66 , 67 , 68 ]: where the subscripts i = f or s represent the bulk fluid and solid domain, respectively. In this way, and denote the electrostatic potential phasor within the solution and block, respectively.…”

An open-source programmable smart pipette for portable cell separation and counting

“…On the other hand, active approaches typically exhibit high uidic controllability and are easy to generate high-pressure conditions, despite requiring external pumping and control equipment. [27][28][29][30][31][32][33][34][35][36][37] Peristaltic pumping mechanisms have been integrated into microuidic devices by sequentially latching microuidic pneumatic valves with high pressure sources and pneumatic controllers, 27,28 and by directly pressurizing elastomeric channels with Braille pins 29 or rotating magnets. 30 Electrokinetic pumps are suitable for uid handling at microand nano-scales, and have been used for biomolecular separation.…”

“…30 Electrokinetic pumps are suitable for uid handling at microand nano-scales, and have been used for biomolecular separation. [31][32][33][34] Centrifugal pumping methods provide a simple and versatile way to pump, mix, and separate uids on a spinning disk, and have been used to develop integrated microuidic systems with a combination of on-disk ltration and sensing mechanisms. 35,36 Compared to the passive approaches, these active technologies can generate a wider range of ow rates, with a higher level of ow controllability.…”

Simulation analysis of rectifying microfluidic mixing with field‐effect‐tunable electrothermal induced flow

“…Unlike this surface flow, ACET arises from smeared structural polarization, where charged ions are induced across a temperature gradient within the fluid bulk due to either Joule heating or externally applied heat source . The motion of the induced spatial charge in an electric field drags the surrounding medium along through viscous effect, resulting in steady electroconvection of aqueous solution in an oscillating electric field . Since the electrothermal body force acting on each liquid element is proportional to the electrical conductivity of buffer medium, it is particularly effective to utilize ACET to drive biological samples of high conductivities within the range of 0.05–2 S/m.…”