A Multichannel Electroosmotic Flow Pump Using Liquid Metal Electrodes

Injecting a room-temperature liquid metal into microchannels offers a simple, rapid, and low-cost method of fabricating microfluidic electrodes. In this work, these electrodes are used to develop a multichannel electroosmotic flow pump for high-flow-rate microfluidic bio analysis applications. In this pump, two identical square-wave shaped liquid metal electrodes were located at both ends of pumping channels on the same horizontal level, and were separated by polydimethylsiloxane gaps from the pumping channels. To test the pumping performance, fluorescent particles were diluted with deionized water and injected into the pumping channels to measure the flow velocity. The results show that the pump with five parallel pumping channels can drive water at a speed of 4.63–45.76 μm/s with applied voltage of 300–1000 V, when the pumping channels are 30 μm high, and 250 μm long with 30-μm polydimethylsiloxane gaps. It can reach its highest possible flow rate of 325 nl/min when the applied voltage reaches its limit 3900V (150 μm long pumping channels, 150 μm long nonpumping channels and 30 μm PDMS gap with 10 parallel pumping channels). This EOF pump should be potential in many high-flow-rate microfluidic applications.