Oxidation potentials oligomers

The ideal electropolymerization scheme (Eq. (5.5.39)) is further complicated by the fact that lower oligomers can react with nucleophilic substances (impurities, electrolyte anions, and solvent) and are thus deactivated for subsequent polymerization. The rate of these undesired side reactions apparently increases with increasing oxidation potential of the monomer, for example, in the series ... 

The polmerisation reaction proceeds between the radical cations of the monomer and those of the continuing forming oligomers since the latter, following the growth of the chain length, acquire an oxidation potential... 

An alternative way to get better structural regularity might be to begin with bithiophene or terthiophene where some of the inter-ring bonds in the polymer are formed before the polymerization and these monomers have lower oxidation potentials (thiophene 1.6 V, bithiophene 1.2 V and terthiophene 1.0 V v SCE). Polymerizations of both bithiophene 143) and terthiophene 144) have been described but there is some doubt about whether the polymers derived from oligomers are more regular or... 

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