Investigation of redox activity in the napthalenediimide-poly(3,4-ethylenedioxythiophene) cross-linked polymers

Electroactive polymers, based on the concept of linking a redox-active core to a backbone with high electronic conductivity, are a class of interesting materials because of the possibility to independently control different properties like electrochromic contrast, conductivity, charge capacity and redox potential window by the proper choice of the two distinct components employed. In this regard, we recently developed a new napthalenediimide-poly(3,4-ethylenedioxythiophene) crosslinked polymer, which was applied in electrochromic and energy storage devices. In this paper the electrochemical characterization of the polymer by cyclic voltammetries and electrochemical quartz crystal microbalance investigations is described. The redox process of the polymer backbone shows the characteristic features of p-doping conducting polymers while the napthalenediimide redox units have a bi-electronic molecular like electrochemistry that strongly depends on the electrolyte cation. The polymer mass change during the voltammetric cycles reveals the role of the solvent in balancing the mass flux across the layer.