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Published 2003 | Published + Accepted Version
Journal Article Open

Experimental test of scaling of mixing by chaotic advection in droplets moving through microfluidic channels

Abstract

This letter describes an experimental test of a simple argument that predicts the scaling of chaotic mixing in a droplet moving through a winding microfluidic channel. Previously, scaling arguments for chaotic mixing have been described for a flow that reduces striation length by stretching, folding, and reorienting the fluid in a manner similar to that of the baker's transformation. The experimentally observed flow patterns within droplets (or plugs) resembled the baker's transformation. Therefore, the ideas described in the literature could be applied to mixing in droplets to obtain the scaling argument for the dependence of the mixing time, t ∼ (aw/U)log(Pe), where w [m] is the cross-sectional dimension of the microchannel, a is the dimensionless length of the plug measured relative to w, U [m s^−1] is the flow velocity, Pe is the Péclet number (Pe = wU/D), and D [m^2 s^−1] is the diffusion coefficient of the reagent being mixed. Experiments were performed to confirm the scaling argument by varying the parameters w, U, and D. Under favorable conditions, submillisecond mixing has been demonstrated in this system.

Additional Information

© 2003 American Institute of Physics. Received 11 July 2003; accepted 6 October 2003. This work was supported by ONR Young Investigator Award (N00014-03-10482), the Camille and Henry Dreyfus New Faculty Award, the Research Innovation Award from Research Corporation, the NIH (R01 EB001903), Chicago MRSEC funded by NSF, and Predoctoral Training Grant (H.S.) of the NIH (GM 08720). This work was performed at the Chicago MRSEC Microfluidic Facility. Photolithography was performed (by H.S.) at MAL of UIC. We thank Prof. H. A. Stone, Prof. A. D. Stroock, and Prof. J. M. Ottino for helpful discussions.

Attached Files

Published - Ismagilov_APL_2003_83_4664_Song_Experimental_Test_Scaling_Chaotic_Mixing_Droplets.pdf

Accepted Version - nihms14599.pdf

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Ismagilov_APL_2003_83_4664_Song_Experimental_Test_Scaling_Chaotic_Mixing_Droplets.pdf
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Additional details

Created:
August 22, 2023
Modified:
October 24, 2023