Electro-osmotic control of the interface position of two-liquid flow through a microchannel

This paper presents theoretical and experimental investigations of the pressure-driven two-liquid flow in microchannels with the AN electro-osmosis effect. For fully developed, steady state, laminar flow of two liquids under the combined effects of pressure gradient, electro-osmosis and surface charges at the liquid–liquid interface, we have derived analytical solutions that relate the velocity profiles and flow rates to the liquid holdup, the aspect ratio of the microchannel, the viscosity ratio of the two liquids and the externally applied electric field. It was shown that adjusting the externally applied electric field could control the fluid interface position precisely. The prediction from the proposed model compares very well with measured data.

[1]  Nam-Trung Nguyen,et al.  Nonlinear diffusive mixing in microchannels: theory and experiments , 2004 .

[2]  Ryutaro Maeda,et al.  A polydimethylsiloxane (PDMS) deformable diffraction grating for monitoring of local pressure in microfluidic devices , 2002 .

[3]  Jr-Lung Lin,et al.  Numerical simulation of electrokinetic focusing in microfluidic chips , 2002 .

[4]  B. Weigl,et al.  Lab-on-a-chip sample preparation using laminar fluid diffusion interfaces – computational fluid dynamics model results and fluidic verification experiments , 2001, Fresenius' journal of analytical chemistry.

[5]  Gwo-Bin Lee,et al.  Multiple injection techniques for microfluidic sample handling , 2003, Electrophoresis.

[6]  Gwo-Bin Lee,et al.  Micromachined pre-focused 1×N flow switches for continuoussample injection , 2001 .

[7]  R. G. Cox.  Electroviscous forces on a charged particle suspended in a flowing liquid , 1997, Journal of Fluid Mechanics.

[8]  F. Erchiqui,et al.  Pressure gradient and electroosmotic effects on two immiscible fluids in a microchannel between two parallel plates , 2005 .

[9]  N. Nguyen,et al.  Interface control of pressure-driven two-fluid flow in microchannels using electroosmosis , 2005 .

[10]  Kim Tiow Ooi,et al.  Transient two-liquid electroosmotic flow with electric charges at the interface , 2005 .

[11]  Chun Yang,et al.  Two-fluid electroosmotic flow in microchannels. , 2005, Journal of colloid and interface science.

[12]  D. Saville.  Electrokinetic Effects with Small Particles , 1977 .

[13]  R. Aigner,et al.  Silicon microphone based on surface and bulk micromachining , 2001 .

[14]  Gwo-Bin Lee,et al.  Micromachined pre-focusedM×Nflow switches for continuous multi-sample injection , 2001 .

[15]  Lung-Ming Fu,et al.  Electrokinetic focusing injection methods on microfluidic devices. , 2003, Analytical chemistry.

[16]  P. Dasgupta,et al.  Microscale continuous ion exchanger. , 2002, Analytical chemistry.

[17]  J. Chai,et al.  Joule heating effect on electroosmotic flow and mass species transport in a microcapillary , 2004 .

[18]  Arthur Brunnschweiler,et al.  Fabrication and test of thermal vertical bimorph actuators for movement in the wafer plane , 2001 .

[19]  Prashanta Dutta,et al.  Electroosmotic Flow Control in Complex Microgeometries , 2000, Micro-Electro-Mechanical Systems (MEMS).

[20]  R. Probstein.  Physicochemical Hydrodynamics: An Introduction , 1989 .

[21]  B. Finlayson,et al.  Quantitative analysis of molecular interaction in a microfluidic channel: the T-sensor. , 1999, Analytical chemistry.

[22]  David F Fletcher,et al.  Hydrodynamic control of the interface between two liquids flowing through a horizontal or vertical microchannel. , 2004, Lab on a chip.