A 2ND TRANSMISSION-LINE MODEL FOR CONDUCTING POLYMERS

A transmission line model for charge conduction in conducting polymers is proposed in which one rail describes the motion of the ions. The motion of the electrons in the polymer is assumed to be controlled by the rate at which electrons hop from one polymer chain to another: this is modelled as a series of wires and resistances where each resistance also has a capacitance in parallel with it. The ac impedance of the transmission line is derived. A case diagram with five different cases is constructed. Expressions are also obtained for the impedance with 1, 2 or 3 jumps. Comparison of the theoretical and experimental results shows that the only model that will fit the data is an equivalent circuit with a single resistance and a single capacitance.