| The ion transport properties and electrochemistry of chemically prepared polypyrrole/poly(styrene-4-sulfonate), poly(3,4-ethylenedioxythiophene)/poly(styrene-4-sulfonate), and electrochemically prepared poly(3,4-ethylenedioxythiophene)/poly(styrene-4-sulfonate) composites have bow investigated by cyclic voltammetry and impedance spectroscopy in a variety of electrolyte solutions. These polymers exhibited facile electrochemistry, fast ion transport, and good electrochemical stability. The chemically prepared polymers are approximately ten times more porous than their electrochemically prepared counterparts, and therefore have ionic conductivities that we higher by a similar factor and show less potential dependence. The ionic conductivities of these polymers are strongly dependent an the concentrations and conductivities of the electrolyte solution used. At low electrolyte concentrations, the ionic conductivities of these polymers also show some potential dependence. It is concluded that these polymers consist of permselective polymer phases containing incorporated counter-ions and pores containing the electrolyte solution. The incorporated ions account for the dependence of ionic conductivity on the applied potential and the polymer's intrinsic ionic conductivity, while the electrolyte solution in the pores explains the strong dependence of ionic conductivity on the solution concentration and conductivity. In high concentration electrolyte solutions, ion transport is dominated by electrolyte in the pores, while at low electrolyte concentrations, incorporated ions in the polymer phases become significant. |
