Development of Electrohydrodynamic Flow Cells for the Synthesis of Conducting Polymers

Abstract

This chapter presents a method of characterizing the efficiency and performance of electrochemical flow cells utilizing three-dimensional reticulated vitreous carbon foam electrodes. Cell-design characterization is critical for the successful implementation and scale-up of electrochemical cells, especially with respect to the scale-up from laboratory to prototype and commercial conducting polymer synthesis. Two electrochemical cell designs were developed “in-house” at the Intelligent Polymer Research Institute (IPRI) by utilizing porous reticulated vitreous carbon (RVC-ERG Aerospace) foam electrodes. To establish that the electrochemical cells were operating at optimal efficiency, a series of standardized tests were developed so that different cells could be compared to one another. The cells were modeled as a Plug Flow Reactor type of reactor. Parameters valid for continuous flow reactors are based upon the assumption of mass transport–limited conditions. Analysis of the current efficiency parameters for the cell designs indicated that at + 0.8 V, the designs had efficiencies of 99% or better. At large residence times, or low flow rates, the mass-transfer process in the sandwich configuration is slightly higher. At shorter residence times, or higher flow rate, the cell designs have similar mass-transfer characteristics because of greater turbulence induced within the reticulated vitreous carbon (RVC) electrodes at higher flow rates. The effect of this turbulence is characterized by the rapid increase in mass transport at lower residence times. The relationship of space-time yield to residence time shows that the sandwich configuration is most efficient at all flow rates investigated.