| Abstract
| - Electrochemically prepared poly(3,4-ethylenedioxythiophene) (PEDT) poly(styrenesulfonate)(PSS), produced from acidic (PSSH) and basic (PSSNa) PSS, was characterized by cyclic voltammetryCV, UV−vis spectroscopy, in situ conductivity, and XPS spectroscopy and was compared withelectrochemically prepared PEDT/tosylate and chemically prepared PEDT/PSS. CV analysis shows thatthe polymer synthesis is strongly affected by the nucleophilic character of the counteranion. AlthoughCV and UV−vis spectroscopy show that the structure and degree of polymerization (oligomeric, ca. 10EDT units) of the PEDT backbone is the same for all polymers, XPS is able to explain the differentconductivity values for these materials (ranging from 1 S cm-1 for PEDT/PSSNa to 400−450 S cm-1 forPEDT/tosylate) based on doping level and composition. In particular, critical results are observed to bethe ratios between sulfonate and thiophene units in the polymers: the higher the PEDT concentration,the higher the conductivity. XPS also explains by solvent-induced nanometer-scale segregation betweenPEDT/PSS and excess PSS particles the often reported conductivity enhancement of chemically preparedPEDT/PSS upon treatment with polar solvents.
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