Jump to main content
Jump to site search

Issue 3, 2002
Previous Article Next Article

Characterization and optimization of slanted well designs for microfluidic mixing under electroosmotic flow

Author affiliations

Abstract

Recently, a series of slanted wells on the floor of a microfluidic channel were experimentally shown to successfully induce off-axis transport and mixing of two confluent streams when operating under electroosmotic (EO) flow. This paper will further explore, through numerical simulations, the parameters that affect off-axis transport under EO flow with an emphasis on optimizing the mixing rate of (a) two confluent streams in steady-state or (b) the transient scenario of two confluent plugs of material, which simulates mixing after an injection. For the steady-state scenario, the degree of mixing was determined to increase by changing any of the following parameters: (1) increasing the well depth, (2) decreasing the well angle relative to the axis of the channel, and (3) increasing the EO mobility of the well walls relative to the mobility of the main channel. Also, it will be shown that folding of the fluid can occur when the well angle is sufficiently reduced and/or when the EO mobility of the wells is increased relative to the channel. The optimum configuration for the transient problem of mixing two confluent plugs includes shallow wells to minimize the well residence time, and an increased EO mobility of the well walls relative to the main channel as well as small well angles to maximize off-axis transport. The final design reported here for the transient study reduces the standard deviation of the concentration across the channel by 72% while only increasing the axial dispersion of the injected plug by 8.6 % when compared to a plug injected into a channel with no wells present. These results indicate that a series of slanted wells on the wall of a microchannel provides a means for controlling and achieving a high degree of off-axis transport and mixing in a passive manner for micro total analysis system (μTAS) devices that are driven by electroosmosis.

Back to tab navigation

Publication details

The article was received on 14 Mar 2002, accepted on 06 Jun 2002 and first published on 18 Jun 2002


Article type: Paper
DOI: 10.1039/B202631G
Lab Chip, 2002,2, 135-140

  •   Request permissions

    Characterization and optimization of slanted well designs for microfluidic mixing under electroosmotic flow

    T. J. Johnson and L. E. Locascio, Lab Chip, 2002, 2, 135
    DOI: 10.1039/B202631G

Search articles by author

Spotlight

Advertisements