Counterions in Chemically Polymerized PEDOT

The number of PEDOTrcounterion complexes generated by chemical polymerization is smaller than that for electrochemical polymerizahon. This is due to the fact that the oxidahon agent itself is typically a salt and its anion becomes the counterion for the PEDOT complex. If addihonal ions are added to the reaction mixture, mixed complexes are generated. 

The original work of Jonas and Hey wang points to some of the most important oxidation agents. The authors used iron(lll) chloride, iron(lll) tosylate, or ammoniumperoxodisulfate resulting in chloride, tetrachloroferrate, tosylate, or sulfate as counterions. 

Kirchmeyer and Jonas have reported the use of iron(III) camphor sulfonate, iron(III) phenol sulfonate, and iron(III) methanesulfonate as oxidation agents. The use of camphor sulfonate resulted in highly conductive films with a specific conductivity of more than 1000 S/cm. 

Kudoh et al. have polymerized EDOT in the presence of sodium alkyl-naphthalenesulfonate with different alkyl chain lengths and an average 

The use of peroxodisulfate as oxidahon agent results in films with sulfate as counterion as reported in the original work by Jonas and Heywang. The use of sulfate as counterion is limited as Kirchmeyer and Reuter later showed at lower concentrations of EDOT sulfate is insufficient as the counterion for the polymerization to proceed and additional coimterions such as PSS are required. 

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