Free Surface Microfluidics Based On Electrowetting

Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
Juan David Gutierrez-Franco , University of California, Santa Barbara, Santa Barbara, CA
Meysam R. Barmi , University of California, Santa Barbara, Santa Barbara, CA
Carl D. Meinhart, Ph.D. , University of California, Santa Barbara, Santa Barbara, CA
Multiple microfluidic devices such as Lab-on-a-Chip and microarrays are currently being used in various applications in biology and chemistry. Some of these devices use electrowetting as means of moving or mixing droplets to perform desired tasks. By applying electric potential to droplets, the wetting properties of the surface can be altered and thus allowing movement of the droplet. In this project, we intend to move and mix two droplets containing different chemicals using electrowetting. Following the mixing of the droplets, we want to evaporate the solvent by controlling the surface temperature with a resistance temperature detector. Different voltages, frequencies, dielectrics and molarity of solutions will be experimented to find a set up that requires less voltage to move the droplets. In addition, numerical simulation will be performed using COMSOL Multiphysics to find the electric field around the droplet due to the applied voltage to the electrodes. Initial results have shown that at a frequency of 1 kHz the 1M KCl solution has a lower activation voltage (4Vpp) on a gold electrode with no electrolysis occurring. We expect to be able to determine the best set up that requires lower voltage for droplet movement and evaporation.