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Issue 34, 2017
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Inertio-elastic flow instabilities in a 90° bent microchannel

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Biological samples having viscoelastic properties are frequently tested using microfluidic devices. In addition, viscoelastic fluids such as polymer solutions have been used as a suspending medium to spatially focus particles in microchannels. The occurrence of flow instability even at low Reynolds number is a unique property of viscoelastic fluids. In this study, we report the instability in viscoelastic flow for a channel having a 90° bent geometry, which is a characteristic of many microfluidic devices. Interestingly, we observed that the flow instability in aqueous poly(ethylene oxide) (PEO) solution occurs when the concentration of PEO is as low as 50 ppm. We systematically investigated the effects of the polymer concentration, flow rate, and elasticity number on the flow instability. The results show that the flow is stabilized in shear-thinning fluids, whereas the flow instability is amplified when both elastic and inertial effects are pronounced. We believe that this study is useful to design microfluidic devices such as cell-deformability measurement devices based on viscoelastic particle focusing.

Graphical abstract: Inertio-elastic flow instabilities in a 90° bent microchannel

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Publication details

The article was received on 07 Jul 2017, accepted on 26 Jul 2017 and first published on 27 Jul 2017

Article type: Paper
DOI: 10.1039/C7SM01355H
Citation: Soft Matter, 2017,13, 5656-5664
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    Inertio-elastic flow instabilities in a 90° bent microchannel

    J. Kim, S. O. Hong, T. S. Shim and J. M. Kim, Soft Matter, 2017, 13, 5656
    DOI: 10.1039/C7SM01355H

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