Simulation and experimental characterization of electroosmotic flow in surface modified channels

    Authors

    S. Krishnamoorthy; J. Feng; A. C. Henry; L. E. Locascio; J. J. Hickman;S. Sundaram

    Comments

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    Abbreviated Journal Title

    Microfluid. Nanofluid.

    Keywords

    electroosmosis; polymer devices; surface oxidation; simulation; dispersion; MICROFLUIDIC DEVICES; POLYELECTROLYTE MULTILAYERS; CAPILLARY-ELECTROPHORESIS; RECTANGULAR MICROCHANNELS; NUMERICAL-SIMULATION; TRANSPORT; HETEROGENEITY; SPHERES; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, ; Fluids & Plasmas

    Abstract

    Covalent surface modification techniques, in particular surface oxidation procedures, have been employed as a mean to modify polymer microfluidic channels for the purpose of modulating microflow. The focus of this work is to experimentally and computationally characterize electroosmotic flow (EOF) to understand the impact of surface modifications and buffer pH on sample mixing and dispersion. The experimental results are used to calibrate and validate the simulation model that solves the Navier-Stokes equation for fluid flow and Poisson equation to resolve external electric field. Experimental and simulated results are presented for hybrid microfluidic systems, consisting of both pristine polymer surfaces and chemically modified polymer surfaces. The results show that the selective surface modification induces hydrodynamic pressure gradient, leading to enhanced sample dispersion. The mass flow rate increases linearly with the level of oxidation. All channels (pristine, oxidized, and hybrid) showed an increasing EOF with increasing pH until the near neutral regime (7 < pH < 9), where the EOF leveled off at a maximum value-behavior that is typical of a microchannel with negative surface moieties populating its surface.

    Journal Title

    Microfluidics and Nanofluidics

    Volume

    2

    Issue/Number

    4

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    345

    Last Page

    355

    WOS Identifier

    WOS:000240036600007

    ISSN

    1613-4982

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