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Micropumps that can be directly integrated into microelectronic devices or microchannel heat sinks are of great interest due to performance, reliability, packaging and cost issues. One alternative is to generate the required flow directly in the microfluidic channels by inducing strong electromechanical forces in the fluid using integrated microelectrodes. In this work, a novel microfluidic pumping approach using traveling-wave dielectrophoresis (twDEP) of microparticles is presented. The dielectrophoretic motion of small particles arises when the suspended particles in a fluid medium are exposed to non-uniform electric fields causing interaction between the induced dipole on the particles and the fields. As the particles move, the surrounding fluid is dragged in the same direction due to viscous effects. The fluidic driving mechanisms due to the particle-fluid and particle-particle hydrodynamic interactions under twDEP are analyzed, and quantitative information on the induced flow field is obtained from numerical simulations. Experimental measurements of the flow velocity in a prototype DEP micropumping device using micro-particle image velocimetry show satisfactory agreement with the numerical predications. Results from this work indicate that the DEP-induced micropumping scheme holds promise for devising chip-integrated micropumping systems for thermal management.
Date of Conference: 28-31 May 2008