Alternating current (AC) electroosmotic micropumps are suggested to be powerful tools for electrolyte dosing in various micro and nanofluidic systems. These pumps are able to manipulate small volumes of liquid samples and involve no moving parts. The pumps find their use in a variety of bioapplications or clinical diagnostics. The micropump is realized by an array of microelectrodes coated along the microchannel, on which an ac electric field is applied. The ac voltage is typically in the range of few volts. Theoretical models describing the ac electroosmotic transport usually consider the Coulombic polarization of the microelectrodes. However, Faradaic currents can occur in such systems as a result of electrochemical reactions. Here we present a mathematical model of an ac electroosmotic system with electrochemical reactions. The model is based on the balances of mass and electric charge and the kinetic equations for the electrode reaction. The theory of the electrolyte dynamics at polarized surfaces for larger applied voltages taking into account the steric effects (formation of condensed ionic layers) has been also published by other authors. The aim of our future work is to study the effect of Faradaic currents on the behavior of the ac electroosmotic micropumps and compare the obtained predictions with those given by the models considering the condensed layer formation.
展开▼
