Mixers and Pumps for Microfluidic Systems, based on Conducting Polymer Oxidation Wave

K. Kannappan, G. Bogle, J. Travas-Sejdic, and D.E. Williams
University of Auckland, Auckland, New Zealand
Published in 2010

Electrochemically-active conducting polymers (ECP) swell or shrink in response to ion and solvent incorporation or ejection as a result of electrochemical reaction of the polymer. When anodic potential is applied to an electrode attached to one end of ECP strip, the oxidation process starts from the electrode and proceeds along the polymer, propagating as a wave. This wave is driven as a consequence of the electrochemical reactions and would be coupled to a propagating front of compositional change. This property of the ECP can be used to design pumps and mixers for microfluidic systems. We in this paper have modeled the oxidation wave propagation and its influence in pumping and mixing of electrolytes in a micro-channel using COMSOL. The swelling and wave propagation of the conducting polymer was modeled using the moving mesh method (ALE) and we here have solved the coupled convection-diffusion equation with the Navier-Stokes equation for finding the velocity and concentration changes in the electrolyte.