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Thermocapillary valve for droplet production and sorting

C. N. Baroud·J. -P. Delville·F. Gallaire·R. Wunenburger
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Abstract

Droplets are natural candidates for use as microfluidic reactors, if active control of their formation and transport can be achieved. We show here that localized heating from a laser can block the motion of a water-oil interface, acting as a microfluidic valve for two-phase flows. A theoretical model is developed to explain the forces acting on a drop due to thermocapillary flow, predicting a scaling law which favors miniaturization. Finally, we show how the laser forcing can be applied to sorting drops, thus demonstrating how it may be integrated in complex droplet microfluidic systems.

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C. N. Baroud, J. -P. Delville, F. Gallaire, R. Wunenburger. 2006-11-17. Thermocapillary valve for droplet production and sorting. https://doi.org/10.1103/physreve.75.046302

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