Spontaneous pulse generation in a steady channel flow of a colloidal suspension -- the role of dissolved gas

ORAL

Abstract

We introduce a phenomenon that is observed when deionized (DI) water with suspended charged particles flows through a single microfluidic channel. When an aqueous suspension of amine-modified, positively charged polystyrene particles (volume fraction $= 0.01$) flows steadily through a serpentine polydimethylsiloxane (PDMS) channel, a pulse of particles is generated, which then flows through the channel at a slower speed than the mean flow velocity. We quantify the results and rationalize the observations by considering the diffusiophoresis of charged particles driven by gas leakage through the permeable PDMS walls. A mathematical model will be compared with the experimental observations.

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Authors

  • Suin Shim

    Princeton University

  • Orest Shardt

    University of Limerick

  • Howard A. Stone

    Princeton University, Princeton University Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, USA, Princeton Univ, Department of Mechanical and Aerospace Engineering, Princeton University