Advances in redox-magnetohydrodynamic (RMHD) pumping via electrochemistry of PEDOT-modified electrodes

by Nash, Christena K.; Fritsch, Ingrid

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Redox-MHDs (RMHD) is a microfluidic technique that takes advantage of fluid flow produced by a body force, FB, which is defined by a simple right hand rule: FB = j x B, where the ionic c.d., j, generated through oxidn. or redn. of redox species at electrode surfaces, is perpendicular to a magnetic field, B. The presence of redox species in soln. can generate high currents while keeping applied voltages low, but could interfere with electrochem. detection or degrade biol. species if RMHD were to be used for lab-on-a-chip applications. The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT),electropolymd. directly onto the electrodes, substituted for soln. redox species, thereby allowing expansion into more LOAC applications (e.g. hand-held environmental anal. and point-of-care diagnostics). PEDOT-modified electrodes are electrochem. reversible, exhibit good stability, and are capable of initially high currents. Flow patterns at multiple electrode geometries were investigated as well as pumping methods to tune flow for different applications.