Studies on conjugated fluoro‐polymers II. Characterization and electrical conductivity of polyperfluorobutyne‐2

Abstract

Polyperfluorobutyne-2 (PPFB), a conjugated polymer, was characterized with IR, W-VIS, fluorescence spectra etc. The electrical conductivities of the polymer doped with various dopants were investigated. The effect of the molecular structure of PPFB on the electrical properties was discussed. IntwdoctionConjugated polymers are currently of wide interest because of their unique electrical properties.l-$ Polyacetylene, the simplest conjugated polymer, has been extensively investigated as a model of conductive polymers. However, the environmental instability of the polymer seriously prevents it from the practical uses. In addition, processing of polyacetylene is difficult because of its insolubility and infusibility. It has been well known that fluorine-containing polymers are expected to show unique chemical and physical properties due to the effect of fluorine atoms in the molecule. To date, however, there have been few reports on the electrical properties of fluorine-containing conjugated polymers.There are some reports on the preparation of polyfluoroacetylene and its derivatives. But all of them, similar to polyacetylene, are insoluble and infu~ible.~ Rubner et aZ.5 reported that the conductivity of polytrifluoromethylacetylene doped with Ia was increased by 5 orders of magnitude from S / cm to 10-5 S/cm, however, the increase in conductivity is rather the result of iodine adsorption than the formation of a cbarge-transfer complex. Several synthetic methods of polyperfiuorobutyne-2 have been reported,6 but all of the polymers obtained are also insoluble, infusible, colorless and lack of absorption in the visible region. Apparently, the polymer backbone is not conjugated. Huang et aI. ' have prepared polyperfluorobutyne-2 by polymerization of the corresponding monomer. The polymer obtained is a brown and lustrous solid, soluble in common organic solvents and air stable, but its chemical structure and the electrical conductivities were not studied.The present article describes the characterization and electrical properties of polyperfluorobutyne-2 obtained by our method. Experimental MaterialsSolvents (THF, benzene) were dried by refluxing over CaH, followed by careful distillation under nitrogen. Pyridine was dried over NaOH tollowed by distillation and