Conductive and magnetic properties of poly(3,6-bis(2-(3,4-ethylenedioxy)thienyl)-N-dodecylcarbazole). A polyconjugated polymer with a high spin density polaron state

The polyconjugated bithiophene-carbazole regular copolymer poly(3,6-bis(2-( 3,4-ethylenedioxy)thienyl)-N-dodecylcarbazole), produced by anodic coupling of the relevant monomer in acetonitrile and characterized by cyclic voltam metry, FTIR reflection-absorption, and UV-vis spectroscopy, has been invest igated with electrochemical quartz crystal microbalance, in situ ESR and in situ conductivity techniques. The two isoelectronic oxidation processes pr oduce the radical cation and dication forms of the polymer with charge loca lization at the bithiophene and carbazole subunits, respectively. Following the charge localization, the first oxidation produces a high spin density polymer with 0.25 spins per repeat unit, Furthermore two conductivity maxim a (1 x 10(-3) and 2.5 x 10(-3) S cm(-1)) are shown in correspondence to the redox processes. A comparison is made with the in situ ESR and in situ con ductivity results obtained from poly(N-ethylcarbazole).