Microfluidic Pumping by Micromolar Salt Concentrations

Abstract

An ion-exchange-resin-based microfluidic pump is introduced that utilizes trace amounts of ions to generate fluid flows. We show experimentally that our pump operates in almost deionized water for periods exceeding 24h and induces fluid flows of um/s over hundreds of um. This flow displays a far-field, power-law decay which is characteristic of two-dimensional (2D) flow when the system is strongly confined and of three-dimensional (3D) flow when it is not. Using theory and numerical calculations we demonstrate that our observations are consistent with electroosmotic pumping driven by umol/L ion concentrations in the sample cell that serve as 'fuel' to the pump. Our study thus reveals that trace amounts of charge carriers can produce surprisingly strong fluid flows; an insight that should benefit the design of a new class of microfluidic pumps that operate at very low fuel concentrations.

15 pages, 10 figures, 1 table

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• Controlled assembly of single colloidal crystals using electro-osmotic micro-pumps
• Chemical Power for Microscopic Robots in Capillaries
• Moving Charged Particles in Lattice Boltzmann-Based Electrokinetics
• The Efficiency of Self-Phoretic Propulsion Mechanisms with Surface Reaction Heterogeneity
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Cited by in corpus (11)

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• A Predictive Model for Convective Flows Induced by Surface Reactivity Contrast
• Non-Monotonic Concentration Dependence of the Electro-Phoretic Mobility of Charged Spheres in Realistic Salt Free Suspensions
• Microstructural diversity, nucleation paths and phase behaviour in binary mixtures of charged colloidal spheres
• Hydrodynamic Stokes flow induced by a chemically active patch imprinted on a planar wall
• Writing in Water
• Ionic self-phoresis maps onto correlation-induced self-phoresis
• Control of Microparticles Through Hydrodynamic Interactions