In this paper, we first report a micropump actuated by surface tension based on continuous electrowetting (CEW). We have used the surface-tension-induced motion of a mercury drop in a microchannel filled with an electrolyte as actuation energy for the micropump. This allows low voltage operation as well as low-power consumption. The micropump is composed of a stack of three wafers bonded together. The microchannel is formed on a glass wafer using SU-8 and is filled with electrolyte where the mercury drop is inserted. The movement of the mercury pushes or drags the electrolyte, resulting in the deflection of a membrane that is formed on the second silicon wafer. Another silicon wafer, which has passive check valves and holes, is stacked on the membrane wafer, forming inlet and outlet chambers. Finally, these two chambers are connected through a silicone tube forming the complete micropump. The performance of the fabricated micropump has been tested for various operation voltages and frequencies. We have demonstrated actual liquid pumping up to 70 μl/min with a driving voltage of 2.3 V and a power consumption of 170 μW. The maximum pump pressure is about 800 Pa at the applied voltage of 2.3 V with an operation frequency of 25 Hz.
Bibliographical noteFunding Information:
Manuscript received June 27, 2001; revised March 23, 2002. This work was supported in part by the Korea Science and Engineering Foundation through the MICROS center at KAIST and the National Research Laboratory program from the Ministry of Science and Technology of Korea. Subject Editor K. D. Wise. K.-S. Yun, I.-J. Cho, and E. Yoon are with the Department of Electrical Engineering and Computer Science, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea (e-mail: firstname.lastname@example.org). J.-U. Bu is with LG Electronics Institute of Technology (LG Elite), Seoul 137-724, Korea. C.-J. Kim is with the Mechanical and Aerospace Engineering Department, University of California, Los Angeles, CA 90095-1597 USA. Digital Object Identifier 10.1109/JMEMS.2002.803286.
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Electrical and Electronic Engineering