The master thesis deals with a conceptual digital microfluidics system, which allows measurements of a droplet oscillation during a contact angle change due to applied electrical voltage. Due to the great advances in the electronics industry and its miniaturisation, there is an increasing need to dissipate large heat fluxes, which current technology is no longer able to provide. Digital microfluidics is therefore a promising solution for the dissipation of high-density heat fluxes and non-uniform temperature distributions in closed chambers of electronic devices. However, we are dependent on the oscillation of the droplet at the voltage switching frequency for the switching frequency and consequently for efficient operation. In the first part of the master thesis, the theoretical basis of surface tension and electro-wetting is described. Commonly used materials and some application concepts of electro-wetting devices are also presented. Two electrode design and fabrication processes for an open-concept electro-wetting device are described in detail. In the first step, a gold layer was sputtered and an appropriate thickness of dielectric was determined and applied. The process of fabricating a second electrode by photolithography and sputtering gold through a metal mask is described. Finally, a hydrophobic layer is applied. At the end of the thesis, the experimental results are presented. We found that the thickness of the dielectric and the applied voltage do not affect the frequency of the droplet oscillation, which is also confirmed from the literature. Only the droplet size has an effect on the oscillation.
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