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
Accepted: 1 December 2007
Published online: 20 February 2008
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.
PACS: 47.57.jb Microemulsions – / 68.08.Bc Wetting – / 47.55.N- Interfacial flows –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2008