Electrodes Modified with Poly(3,4-Ethylenedioxythiophene) Doped with Sulfonated Polyarylethersulfones: Towards New Conducting Polymers

To overcome the well-known technical problems of Poly(3,4-Ethylenedioxythiophene) (PEDOT), i.e. difficult processability and patterning, due to its poor solubility in common organic and inorganic solvents, PEDOTs characterized by a full miscibility in the reaction solvents used, were successfully synthesized by a direct oxidative polycondensation reaction between Ethylenedioxythiophene (EDOT) and an oxidant species, i.e. ferric sulfate, in four organic reaction solvents: N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP). The oxidative polycondensation of EDOT in the presence of Sulfonated Polyarylethersulfone (SPAES) as doping agent characterized by three increasing degree of sulfonation (DS), i.e. 0.5, 0.75 and 1.0 (meq SO3-·g-1 of polymer), was performed for the first time, leading to a new conducting material: PEDOT_SPAES. PEDOT_SPAES can be easily processed and casted onto the surface of glassy carbon electrodes, reaching better electrochemical performances with respect to the precursors. PEDOT_SPAES chemical structure was investigated via wide-angle scattering (WAXS): comparing WAXS spectra of unmodified PEDOT and commercial PEDOT doped with 2-Naphthalenesulfonic acid, having crystalline structures, with the spectra of PEDOT_SPAESs, that are characterized by amorphous structures, it is possible to assess that for the first time PEDOT-based materials doped with SPAES were synthesized.