A NOVEL TYPE OF SEMICONDUCTING POLYMERS - SYNTHESIS AND PROPERTIES OFELECTROCHEMICALLY-DOPED POLYMERS CONTAINING PENDANT OLIGOTHIOPHENES

For the purpose of developing a novel type of electrically conducting polymers, synthesis and properties of electrochemically-doped, non-con jugated vinyl type polymers containing oligothiophenes as pendant grou ps have been studied. New vinyl monomers, 2-[4-(2-thienyl)-phenyl]-5-v inylthiophene and 5-vinyl-2,2':5',2'':5'',2'''-quaterthiophene, have b een synthesized, and electrolytic polymerization carried out by contro lled potential anodic oxidation. The resulting polymers were identifie d as partially oxidized radical cation salts with ClO4- as a dopant, h aving partially cross-linked structures. The polymers undergo reversib le color changes. Electrochemically-doped poly(5-vinyl-2,2':5',2'':5'' ,2'''-quaterthiophene) exhibits room-temperature conductivities of ca. 10(-7) S cm-1 with activation energies of ca. 0.5 eV.