Polyalloocimene, a Novel Nonconjugated Conductive Polymer: The Correct Fundamental Basis for Conductive Polymers

A polymer does not have to be conjugated to become electrically conductive. The correct fundamental basis for a polymer to be conductive is that it must have at least one double bond in the repeat. The magnitude of conductivity increases with the number fraction of the double bonds in the repeat. Polyisoprene, the first known nonconjugated conductive polymer has a double bond number fraction of 1/4 while polyacetylene, the first known conjugated conductive polymer, has a number fraction of 1/2. A new nonconjugated conductive polymer, polyalloocimene, has a double bond number fraction of about 1/3. Consequently, the electrical conductivity, the doping rate and the optical transition energies of polyalloocimene are intermediate between those of polyisoprene and polyacetylene. The magnitude of conductivity has a power law dependence on the number-fraction of double bonds. The optical absorption peak of the radical cation produced upon doping appears at lower energies as the separation between the double bonds decreases. The general mechanism of conductivity going from a nonconjugated structure involving isolated double bonds to a fully conjugated structure has been established.