Synthesis and electrical properties of novel electrochemically-doped vinyl polymers containing ‘end-capped’ quaterthiophene and quinquethiophene as pendant groups

For the purpose of developing a novel class of electrically conducting polymers, electrochemically-doped vinyl polymers containing ‘end-capped’ quaterthiophene and quinquethiophene as pendant groups have been prepared by electrolytic polymerizations of the corresponding vinyl monomers in dichrolomethane containing tetrabutylammonium perchlorate. The electrochemically-doped polymers were identified as partially oxidized radical-cation salts with ClO4− as a dopant, as evidenced from the electronic and infrared absorption spectra and elemental analysis. The eletrochemically-doped polymers containing ‘end-capped’ quaterthiophene (degree of doping: 49%) and quinquethiophene (degree of doping: 66%) as pendant groups exhibited room-temperature conductivities of 3 × 10−8 and 2 × 10−5 S cm−1 with activation energies of 0.49 and 0.32 eV, respectively.