Abstract
The purpose of this thesis is to develop an active micromixer. The fluid is driven by Lorentzforce which is induced by the coupling between a magnetic field in vertical direction and a currentdensity due to ionic motions under an electric field. The deformation and distortion of the fluidinterface enhance mixing. In this article, we simulated the mixing process by CFD-ACE+ anddiscussed different flow patterns under DC and AC driving signals, to help design the suitablespace between two electrodes for the micromixer. In device fabrication, the electrodes weremanufactured by MEMS techniques, and the chamber was made of PDMS by molding. Finally,we combined them with field-generated instruments. In experiment observation, we performeddye experiment and observed the mixing process by optical microscope. Results of the experimentwere compared and discussed with the previous simulations.This research brings out a novel coiled pattern of electrode design. In addition, we utilizedAC signal to reduce bubbles formation and erosion of electrodes. Thus, the device has a betterperformance. The advantages of this active micromixer are simplicity in its structure andfabrication process, great manipulation of fluid, without high voltage signal that gains side effects ofspecimens, and ability to integrate and control in electric circuits. Therefore, we hope the designconcept of the micromixer could apply to biomedical detection, raising its speed and accuracy inthe future.