Enhancement of electrokinetically driven microfluidic T‐mixer using frequency modulated electric field and channel geometry effects

This study reports improved electrokinetically driven microfluidic T‐mixers to enhance their mixing efficiency. Enhancement of electrokinetic microfluidic T‐mixers is achieved using (i) an active approach of utilizing a pulsating EOF, and (ii) a passive approach of using the channel geometry effect with patterned blocks. PDMS‐based electrokinetic T‐mixers of different designs were fabricated. Experimental measurements were carried out using Rhodamine B to examine the mixing performance and the micro‐particle image velocimetry technique to characterize the electrokinetic flow velocity field. Scaling analysis provides an effective frequency range of applied AC electric field. Results show that for a T‐mixer of 10 mm mixing length, utilizing frequency modulated electric field and channel geometry effects can increase the mixing efficiency from 50 to 90%. In addition, numerical simulations were performed to analyze the mixing process in the electrokinetic T‐mixers with various designs. The simulation results were compared with the experimental data, and reasonable agreement was found.

[1]  Che-Hsin Lin,et al.  Microfluidic T-form mixer utilizing switching electroosmotic flow. , 2004, Analytical chemistry.

[2]  N. Nguyen,et al.  Visualizing the transient electroosmotic flow and measuring the zeta potential of microchannels with a micro-PIV technique. , 2006, The Journal of chemical physics.

[3]  Jia-Kun Chen,et al.  Electroosmotic flow mixing in zigzag microchannels , 2007, Electrophoresis.

[4]  D. Erickson,et al.  Influence of Surface Heterogeneity on Electrokinetically Driven Microfluidic Mixing , 2002 .

[5]  Robin H. Liu,et al.  Passive mixing in a three-dimensional serpentine microchannel , 2000, Journal of Microelectromechanical Systems.

[6]  Nadine Aubry,et al.  Electro-hydrodynamic micro-fluidic mixer. , 2003, Lab on a chip.

[7]  P. Stewart,et al.  Rapid Diffusion of Fluorescent Tracers into Staphylococcus epidermidis Biofilms Visualized by Time Lapse Microscopy , 2005, Antimicrobial Agents and Chemotherapy.

[8]  J. M. MacInnes,et al.  Computation of reacting electrokinetic flow in microchannel geometries , 2002 .

[9]  D. Sinton,et al.  A sequential injection microfluidic mixing strategy , 2005 .

[10]  N. Aubry,et al.  Electroosmotic mixing in microchannels. , 2004, Lab on a chip.

[11]  D. J. Harrison,et al.  Micromachining a Miniaturized Capillary Electrophoresis-Based Chemical Analysis System on a Chip , 1993, Science.

[12]  Ping Wang,et al.  Electrokinetic micropump and micromixer design based on ac faradaic polarization , 2004 .

[13]  D. J. Harrison,et al.  A multireflection cell for enhanced absorbance detection in microchip‐based capillary electrophoresis devices , 2000, Electrophoresis.

[14]  E. Biddiss,et al.  Heterogeneous Surface Charge Enhanced Micromixing for Electrokinetic Flows , 2004 .

[15]  Y. Lam,et al.  Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channels , 2006, Electrophoresis.

[16]  Nam-Trung Nguyen,et al.  Efficient mixing of viscoelastic fluids in a microchannel at low Reynolds number , 2006 .

[17]  Sandip Ghosal,et al.  Electrokinetic Flow and Dispersion in Capillary Electrophoresis , 2006 .

[18]  S. Jacobson,et al.  Microfluidic devices for electrokinetically driven parallel and serial mixing , 1999 .

[19]  Chun Yang,et al.  DC-biased AC-electroosmotic and AC-electrothermal flow mixing in microchannels. , 2009, Lab on a chip.

[20]  Ruey-Jen Yang,et al.  Computational analysis of electrokinetically driven flow mixing in microchannels with patterned blocks , 2004 .

[21]  David Sinton,et al.  High-efficiency electrokinetic micromixing through symmetric sequential injection and expansion. , 2006, Lab on a chip.

[22]  T. Johnson,et al.  Rapid microfluidic mixing. , 2002, Analytical chemistry.

[23]  Howard Brenner,et al.  Curvature-Induced Dispersion in Electro-Osmotic Serpentine Flows , 2004, SIAM J. Appl. Math..

[24]  Gwo-Bin Lee,et al.  Electrokinetically driven active micro-mixers utilizing zeta potential variation induced by field effect , 2004 .

[25]  Danesh K Tafti,et al.  Evaluation of microchamber geometries and surface conditions for electrokinetic driven mixing. , 2004, Analytical chemistry.

[26]  V. Hessel,et al.  Micromixers—a review on passive and active mixing principles , 2005 .

[27]  Takehiko Kitamori,et al.  AC electroosmotic micromixer for chemical processing in a microchannel. , 2006, Lab on a chip.

[28]  Nadine Aubry,et al.  Enhancement of microfluidic mixing using time pulsing. , 2003, Lab on a chip.

[29]  Marcos,et al.  Dynamic aspects of electroosmotic flow in rectangular microchannels , 2004 .

[30]  D. Erickson,et al.  Integrated microfluidic devices , 2004 .

[31]  I. Mezić,et al.  Chaotic Mixer for Microchannels , 2002, Science.

[32]  Ursula Bilitewski,et al.  Biochemical analysis with microfluidic systems , 2003, Analytical and bioanalytical chemistry.

[33]  Helen Song,et al.  On-chip titration of an anticoagulant argatroban and determination of the clotting time within whole blood or plasma using a plug-based microfluidic system. , 2006, Analytical chemistry.

[34]  Guann-Pyng Li,et al.  Electroosmotic properties of microfluidic channels composed of poly(dimethylsiloxane). , 2001, Journal of chromatography. B, Biomedical sciences and applications.

[35]  F. Regnier,et al.  A picoliter-volume mixer for microfluidic analytical systems. , 2001, Analytical chemistry.

[36]  D. J. Harrison,et al.  Electrokinetic control of fluid flow in native poly(dimethylsiloxane) capillary electrophoresis devices , 2000, Electrophoresis.

[37]  H. Bau,et al.  A minute magneto hydro dynamic (MHD) mixer , 2001 .

[38]  Arun Majumdar,et al.  Mixing crowded biological solutions in milliseconds. , 2005, Analytical chemistry.