Abstract
A novel electrolysis-bubble-actuated micropump has been successfully developed by utilizing a specific roughness gradient design on the hydrophobic lateral breather which could achieve a net pumping flow. The micropump is implemented by means of electrolysis, surface tension effect and the periodic electrolysis-bubble generation. The advantages of this proposed micropump design not only achieve a net pumping flow but also resolve the disadvantages that exist in the early proposed electrochemical micropumps, such as the complicated time-sequence power control on many pairs of electrodes, the need of large/long nozzle-diffuser structure and the limitation of the sealed reservoir inside the fluidic chip. This micropump with a simple circuit control and without moving parts is suitable for the development of low power-consumption and compact micropumps. Experimental results successfully demonstrate the pumping function of our micropump to continuously push liquid forward via the gradient roughness design and the periodic generation of electrolytic bubbles in a microchannel. Furthermore, experimental results also show that the liquid displacement and pumping rate could be easily and accurately controlled by adjusting the applied voltage with specific operating frequency. A maximum pumping rate of 114 nl/min is achieved for our micropump#1 with a microchannel cross section of 100 μm× 20 μm. In this paper, we describe the theoretical analysis, design, micromachining process, and operating principles, as well as the experimental demonstration of this micropump.