Concerted Ion and Electron Transfer Across Electronically Conductive Polymer Membranes

We describe in this paper an experiment involving an electronically conductive polymer (ECP) which, to our knowledge, has not been described previously. A free-standing ECP (polypyrrole)-based membrane separates a solution of an electron donor from a solution of an electron acceptor. Because the ECP is both electronically and anionically conductive, the membrane can transport electrons from the donor solution to the acceptor solution, and anions in the opposite direction, such that a sustainable electron-transfer reaction is driven across the ECP membrane. We demonstrate such transmembrane electron/ion-transfer processes using both an inorganic and a biochemical electron donor/acceptor system. The biochemical case is of particular interest because we show that the reduced form of the enzyme glucose oxidase can give its electrons directly to the synthetic metal. Direct electron transfer is usually not possible at inorganic metals.