Electrokinetic maneuvering of bubble-driven inertial micro-pumping systems

Abstract

The pumping of an aqueous electrolyte by means of an asymmetrically placed thermal resistor and electrodes is investigated in this work. This device has no moving parts and provides a continuous and controllable pulsating flow, which make it a very attractive and viable option for use on lab-on-a-chip devices. The electric field induced modulation provides a higher degree of control on the mass flow rate, by means of which one can achieve on-the-fly mass flow rate control. The pumping action is achieved by means of a high-pressure bubble generated by actuating a thermal resistor which is located asymmetrically between two reservoirs. The ends of the channel are connected to fluidic columns. The combined action of an applied electric field and a faster refilling of the shorter arm after bubble collapse essentially drive a net amount of electrolyte through the system. We study the influence of the geometric parameters like the location of the heater, channel width and the channel length apart from the physiochemical parameters like the Debye length and the applied field strength on the mass flow rate achieved through this device.