Slow relaxation in conducting polymers

Abstract

The potential at which conducting polymers can be electrochemically doped to the conducting state shifts slowly then the material is maintained in the insulating state. A logarithmic law for the shift as a function of the wait time in the insulating state has been observed over the range ${10}^{\mathrm{\ensuremath{-}}4}$--${10}^{5}$ s. The influence of temperature, pressure, and nature of the electrolyte has been studied. A logarithmic shift is also observed as a function of the scan rate, which indicates that the relaxation process concerns kinetic parameters of the reaction rather than the thermodynamical redox potential. The kinetics of the doping process is shown to obey a universal law, which resembles the aging process of glassy materials.