Electrochemical Determination of Flow Velocity Profile in a Microfluidic Channel from Steady-State Currents: Numerical Approach and Optimization of Electrode Layout

Abstract

In this article, the numerical approach for flow profile reconstruction in a microfluidic channel equipped with band microelectrodes introduced previously by the authors, based on transient currents, is extended to the exclusive use of steady-state currents. It is shown that, although the currents obey steady state, the flow velocity profile in the channel may be reconstructed rapidly with a high accuracy, provided a sufficient number of electrodes performing under steady state are considered. The present theory demonstrates how the electrode widths and sizes of gaps separating them can be optimized to achieve better performance of the method. This approach has been evaluated theoretically for band microelectrode arrays embedded into one wall of a rectangular channel consisting of three, four, or five electrodes, all of which are operated in the generator mode. The results prove that the proposed approach is able to accurately recover the shape of the flow profile in a wide range of Peclet numbers and flow types ranging from the classical parabolic Poiseuille flow to constant electro-osmotic-type flow.