Abstract
We report the production of droplet groups with a controlled number of drops in a microfluidic electro-flow-focusing device under the action of an AC electric field. This regime appears for moderate voltages (500–700 V peak-to-peak) and signal frequencies between 25 and 100 Hz, much smaller than the droplet production rate (\({\sim }\,{500}\) Hz). For this experimental condition the production frequency of a droplet package is twice the signal frequency. Since the continuous phase flow in the microchannel is a Hagen–Poiseuille flow, the smaller droplets of a group move faster than the bigger ones leading to droplet clustering downstream.
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Acknowledgements
The authors would like to acknowledge financial support from Spanish Government Ministry MEC under Contracts DPI2013-46485-C3-1-R and FIS2014-54539-P and Regional Government Junta de Andalucía under Contract P11-FQM-7919. They would also like to acknowledge the technical assistance of S. Schlautman in the fabrication of the microfluidic devices.
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Castro-Hernández, E., García-Sánchez, P., Velencoso-Gómez, A. et al. Droplet group production in an AC electro-flow-focusing microdevice. Microfluid Nanofluid 21, 158 (2017). https://doi.org/10.1007/s10404-017-1995-3
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DOI: https://doi.org/10.1007/s10404-017-1995-3