A hydrophobicity controlled nanofluidic pump

Abstract

In this paper, we present a nanofluidic device utilizing electrically controllable surface tension as the driving force to deliver fluid flow in the order of nano liters per minute or even smaller, without a dedicated actuator. This nanofluidic pump is capable of pumping a continuous liquid column. It also has a built-in metering feature to precisely determine the flow rate without an additional flow sensor. The physics of this micro/nano flow actuation is based on electrowetting-on-dielectric (EWOD) and depicted by Young-Lippmann equation. The device was prototyped by silicon and Pyrex 7740 glass to form a closed microfluidic channel, where the hydrophobic and hydrophilic electrode pads were fabricated alternatively along the fluid path. The experimental results show that water can be electrically actuated successfully to flow in the microchannel at a flow rate of 18 nl/min under a potential of as low as 20 V. This is very attractive for applications which require an ultra miniaturized metering pump operated at a low power.