A modified electroosmotic micromixer for highly miniaturized microchannels

Miniaturization of microchannels leads to low Reynolds number flow. In such a case, electroosmotic force is the best choice to perturb fluid. Due to low Reynolds number, mixing process is one of the major problems in the Lab-On-a-Chip (LOC) or micro Total Analysis Systems (μ-TAS). This paper proposes a novel technique of microchannel fabrication based on surface micromachining, the technology process needs to cover the exciting electrodes by an insulator layer. A more miniaturized electroosmotically actuated micromixer is designed using a novel sinusoidal-shaped electrode patterns to induce chaotic regime. During the fabrication process a sinusoidal-shaped electrode patterns are covered by a thin silicon nitride layer as an insulator layer. Result reveals that the micromixer is able to perturb the low Reynolds number flow, as well as the silicon nitride layer can reduce the high voltage gradient at the sharp corners and edges of the electrodes. The influence of excitation and geometrical parameters on mixing quality is investigated.