Electrochemical generation of interchain σ-couplings within poly-duren-3,4-bi-dioxythiophene (PDbDOT)

Conducting polymers are among the most interesting materials due to their numerous applications ranging from sensing to energy storage devices. Among the different phenomena associated with the electric, electrochemical and optical properties of these macromolecules, charge trapping via σ-couplings remains highly controversial. This work studied the electrochemical generation of σ-couplings between neighboring oligomeric chains by taking advantage of the physicochemical properties of the novel poly-3,4-duren-bi-dioxythiophene (PDbDOT). The double thiophene core, within the monomeric unit, in synergy with the spatial conformation provided by the duren moiety, leads to the generation of 3-D oligomeric networks. This was evidenced by the electric, electrochemical and spectroelectrochemical characterization of PDbDOT and its proper comparison with well-known poly-3,4-alkoxy thiophenes. During the charge/discharge process of PDbDOT the charge carrier transport mechanism is mainly governed by the mixed valence model due to the ordered oligomeric arrangement. Such unconventional excess of interwire charge hopping between oligomers, coupled to the spatial distribution of the polymeric chains, leads to an irreversible σ-charge trapping.