All terrain droplet actuation
Original Entry: Ian Bruce Burgess Fall 2009
M. Abdelgawad, S.L.S. Freire, H. Yang and A.R. Wheeler, Lab on a Chip 8, 672-677 (2008).
This paper introduces a new platform for droplet-based microfluidic manipulation on flexible substrates. Electrowetting forces are applied to drops via copper electrodes embedded in a flexible polyimide film. The electrodes are protected with coatings of poly(dimethylsiloxane) (PDMS) and teflon. Performance properties and applications of these devices are explored. Electrowetting forces were sufficiently strong to drive droplets with sufficiently small volume (<7.3<math>\mu L</math>) up a vertical incline. Droplet actuation in various configurations of the flexible substrate are shown in the figure below.
A large significance of having a flexible platform for microfluidic droplet manipulation is that the device can easily be integrated across different environments. As an example, the authors demonstrate the transport of a water droplet containing the dye methylene blue and glucose across an air-oil interface into a bath of silicone oil.