Redox transformations of electronic polymers as heterogeneous structures

The anodic and cathodic doping-undoping processes of poly-3-methylthiophene (P3MT) and polybithiophene (PBT) were studied in acetonitrilic solutions of tetraethyl- and tetrabutylammonium tetrafluoroborate. It was shown that most of polymer doping charge is involved in quasi-reversible redox transformations: both the doping and undoping processes occur close to the corresponding standard potentials. However, a residual portion of positive or negative doping charge was shown to be conserved in the polymers during their undoping and their redox transformations are strongly hindered. The residual charge formation within non-conducting matrices of the neutral polymers was attributed to the polymer heterogeneity.