Eur. Phys. J. E (2008) 26: 91-96
https://doi.org/10.1140/epje/i2007-10252-x

ISMC-2007

Electrowetting --A versatile tool for controlling microdrop generation

Physics of Complex Fluids, Faculty of Science and Technology, IMPACT and MESA+ Institute, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands

^* e-mail: F.G.J.Malloggi@tnw.utwente.nl

Received: 19 September 2007
Accepted: 1 December 2007
Published online: 20 February 2008

Abstract

Integrating insulator-covered electrodes into a microfluidic flow focusing device (FFD) we demonstrate enhanced flexibility and control of the flow of two non-miscible liquids based on electrowetting (EW). In the parameters space, determined by liquid inlet pressures, we identify a specific region where drops can only be generated and addressed via EW. In this regime we show that the size distribution and the frequency of drop generation can be controlled by the applied voltage and the width of voltage pulses. Moreover it turns out that with EW the drop size and the frequency can be tuned independently. Finally we show that the same drop generation phenomena can also be observed in the presence of surfactants.