AC electro-osmotic micromixer using a face-to-face, asymmetric pair of planar electrodes

作者：Chen Jhih Lin; Shih Wei Hung; Hsieh Wen Hsin^*

来源：Sensors and Actuators B: Chemical , 2013, 188: 11-21.

DOI：10.1016/j.snb.2013.07.012

• AC electro-osmotic flow
• Micromixer
• Asymmetric electrode pair
• Mixing enhancement factor
• Single stranded deoxyribonucleic acids
• Escherichia coli

This paper is the first to report the mixing performance of an AC electro-osmotic (AC-ED) micromixer based on the two sets of vortices generated by a face-to-face, asymmetric pair of planar electrodes. The larger top electrode of the asymmetric electrode pair was rectangular (30 x 60 mm(2)) and the much smaller bottom electrode was also rectangular (500 x 700 mu m(2)) and featured two protrusions. Due to the highly three-dimensional flow pattern generated by the unique shape of the face-to-face electrode pair, the mixing enhancement factor (mixing time by diffusion/mixing time by the micromixer) exhibited by the reported micromixer ranged from 290 to 360 and the mixing performance values were uniform across the entire height of the fluid cavity. The usefulness of the mixer in hybridizing single-stranded deoxyribonucleic acids and mixing Escherichia coli with RNA stains was also demonstrated experimentally. A numerical investigation was conducted to study the three-dimensional AC-ED flow patterns induced by the face-to-face, asymmetric electrode pair. This analysis made it possible to identify a detailed flow pattern and the formation mechanism of the vortices. The confluence of inward AC-ED flows from the edges of the bottom-electrode protrusion locally induced a large inward-pumping force and was responsible for the formation of the four vortices at the four corners of the bottom electrode. The numerical and experimental results of this research provide information that will be useful in future applications and research in the area of microfluidic manipulation.

• 出版日期2013-11