Fibrillar electronically conductive polymers show enhanced rates of charge transport

Abstract

Abstract : Many electronically conductive polymers can be reversibly switched between electronically insulating and electronically conducting states. For polyrrole, this redox switching reaction can be written as - (Pyrrole)-x+ Boron Tetrafluoride Anion 4- ---- -(Py+BF4(-)n - (PY)(x-n)- + ne(-) where Py and Py(+) are reduced and oxidized monomer unites in the polypyrrole film and BF4(-) is a charge balancing counter-ion, initially present in a contacting solution phase. Equation 1 shows that ions must be incorporated into, or expelled from, the polymer phase during the redox switching reaction. In many cases, the rate of this reaction is controlled by ion-transport in the polymer phase (3,4). The switching reaction plays an integral role in nearly all of the proposed applications of electronically conductive polymers (5-7). In most cases, significant benefit would accrue if the rate of this reaction could be accelerated. The above discussion suggests that one approach for enhancing the rate of the switching reaction would be to enhance the rate of charge-transport in the polymer phase. We would have recently described a procedure for controlling the supermolecular structures of electronically conductive polymers (8). This procedure yields polymers with fibrillar supermolecular structures. We have shown the polypyrrole films which have this fibrillar supermolecular structure support higher rates of reductive charge-transport than conventional polypyrrole films. We report preliminary results of these investigation in this communication. Electronically conductive polymers, Polypyrrole, Oxidized monomer units, Supermolecular, Fibrillar supermolecular structure. Charged particles.