title: Quantification of electrical field-induced flow reversal in a microchannel.
abstract: We characterize the electroosmotic flow in a microchannel with field effect flow control. High resolution measurements of the flow velocity, performed by micro particle image velocimetry, evidence the flow reversal induced by a local modification of the surface charge due to the presence of the gate. The shape of the microchannel cross-section is accurately extracted from these measurements. Experimental velocity profiles show a quantitative agreement with numerical results accounting for this exact shape. Analytical predictions assuming a rectangular cross-section are found to give a reasonable estimate of the velocity far enough from the walls.
authors.affiliation: Physics of Fluids Group, Department of Applied Physics, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Pirat
authors.forename: A
authors.initials: A
authors.lastname: Naso
authors.forename: E J
authors.initials: EJ
authors.lastname: van der Wouden
authors.forename: J G E
authors.initials: JG
authors.lastname: Gardeniers
authors.forename: D
authors.initials: D
authors.lastname: Lohse
authors.forename: A
authors.initials: A
authors.lastname: van den Berg
mesh_terms: D004574:Electromagnetic Fields; D053841:Electroosmosis / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D015640:Ion Channel Gating / Q000502:physiology*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D012212:Rheology / Q000295:instrumentation / Q000379:methods*