Innovative Electrode Arrangement for Electrohydrodynamic Pumping

An experimental investigation was conducted to develop an electrohydrodynamic (EHD) pump based on a microelectromechanical system (MEMS) technology. To develop an EHD micropump with enhanced pumping performance, including not only long-term driving but high-pressure generation, two electrode plates were prepared. On one, the electrode pattern was designed as a series of planar comb fingers. The electrodes had a width of 60 mum, with a 120-mum gap between each pair. The gap between the electrode pairs is 480 mum. The other electrode plate was a non-patterned plane surface. The working fluid was confined between the two electrodes, which faced each other with a distance of 100 mum. The overall dimensions of the micropump were 30 times 30 times 5.3 mm. The working fluid used was HFE-7100 (3 M), and all the experiments were conducted inside a class 1000 clean room with controlled moisture content (19.0%) and temperature (295.55 plusmn 0.5 K). The pump generated a maximum pressure of 500 Pa and a maximum flow rate of 6 mL/min. The highest pump performance was 0.25%. Finally, we proposed an EHD pumping mechanism that explains the pressure generation as the emission of positively charged liquid molecules through the hetero-charge layers.