Novel electrical and optical properties of liquid conducting polymers and oligomers

A conducting polymer with highly extended conjugated bonds in its main chain becomes fusible and also soluble in common solvents after the introduction of long side chains, such as alkyl, as a substituent. Because these liquid conducting polymers and oligomers have much smaller band gaps than those of conventional organic liquids, they exhibit relatively high electrical conductivity and also interact with visible light. Therefore, these liquid conducting polymers can be used effectively for fundamental research to clarify the electronic state and transport processes in dielectric liquids. Novel anomalies in electrical conductivity, photoconductivity and luminescence also have been observed in these liquids, and are discussed in terms of the fluctuation of electronic band gap and the interchain interaction, which depends on alkyl side chain length and on its conformation, and therefore on temperature. The unique applications of these liquid conducting polymers and solutions are also discussed. Characteristics of the interface between conducting polymer and dielectric liquids are also found and discussed in terms of electron scavenging of CO₂ in liquid and CO₂ fixation