This paper describes a micro ion drag pump, or an ejection type electro-hydrodynamic (EHD) micropump, using indium-tin-oxide (ITO) planar electrodes to deal with the aging problem in a novel way. The ITO film for the electrodes, which are immersing in the working liquid, prolongs the operation duration of the valveless micropump. It also makes anodic bonding easily and feasible in packaging the glass substrate (with ITO) hermetically with the silicon microchannels. Therefore, the scaling down or the miniaturization of ion drag pumps can be achieved herein. The ITO electrodes could drive the ethyl alcohol to have the maximum volumetric flow rate of 356 nl/min by applying a dc voltage of 61 V. More efforts and improvements on the pumping efficiency as well as the long-term stability of the ITO electrodes are acquired correspondingly.
Sensors and Actuators A: Physical 111(1), pp.118-122