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Abstract

In this paper we present a systematic study of the effect of the substitution pattern in the starting monomers on the resulting properties of some electrodeposited polydidodecylterthiophenes. The compared characterization of p-doping processes in regioregular electropolymerized poly-3‘,4‘- and 3,3‘ ‘-didodecyl-2,2‘:5‘,2‘ ‘-terthiophene is here reported for the first time. The in situ variations of the optical, magnetic, and electrical transport properties have been measured and correlated with the effects associated to the substituent position. An important result was the verification of absorption fine structures in the wavelength range 500 < λ < 620 nm for the optical spectra of the electropolymerized polydidodecylterthiophenes thus confirming the typical features of regioregular polymers. Visible spectra and cyclic voltammetries verified that poly-3,3‘ ‘-didodecyl-2,2‘:5‘,2‘ ‘-terthiophene possessed a more effective electronic conjugation with respect of the other isomer poly-3‘,4‘-didodecyl-2,2‘:5‘,2‘ ‘-terthiophene. On the other hand the latter polymer showed a higher value of the electronic conductivity (33 vs 21 S cm^-1). Such differences were discussed in terms of the effect of the substituent position on the polymers packing and the separation between chains.