THE NONMETALLIC CHARACTER OF SOLVATED CONDUCTING POLYMERS

Theoretical considerations and experimental findings on the electrochemistry of "conducting polymers" (polypyrrole etc.), deposited as thin films on electrodes, are collected and analysed. As the electrode potential is changed, the polymer assumes a new equilibrium state characterized by a new value of the chemical potential of electrons, i.e. the ratio between the concentration of oxidized and reduced polymer sites varies. Therefore, the electrical potential of the solvated polymer phase is shown to remain largely unchanged. The solvated conducting polymers are therefore concluded to be better described as special redox polymers than as metals. The consequences of this fact for the analysis of charge transport processes and the electrocatalytic behaviour of conducting polymers are discussed from a fundamental point of view.