Preparation of a Variety of Polymeric Conductors from Diacetylenes

Abstract

Several different structures of conducting polymers have been synthesized from diacetylenes including non-substituted one, i.e. butadiyne (BDy).

Semiconducting polymer single crystals were obtained by thermally or y-ray induced doping-polymerization of diacetylenes, where chemical doping had been made before rigid polymer crystal lattice was formed.

Conductivities attained were in the range of 10⁻-^{4 ∼ −7} S/cm, depending on compounds (2,4-hexadiyne-1,6-diol p-toluenesulfonate, 1,6-dicarSazoyl-2,4-hexadiyne etc.) and dopants (I₂, SbF₅, AgClO₄, FeCl₃, SO₃, etc.). The doping-polymerization method was found to be applicable also for semiconducting thin layer formation. γ-Ray induced post-polymerization of BDy in the solid-state explosively produced a carbon-like polymer with the conductivity of 10⁻-² S/cm, whereas spontaneous polymerization of BDy in solution gave a soluble brownish polymer whose conductivity increased upto 10⁻-⁴ S/cm upon I₂ doping. Oxidative coupling of BDy in solution resulted in a black powdery polymer formation. Conductivity of the poly-yne was improved from 10-^ll to 10⁻-⁴ S/cm by I₂ doping. Two kinds of metal containing polymers were obtained by the reaction of BDy with metal halides in basic solution. Upon I₂ doping, conductivities of the peletized BDy-Cu polymers were enhanced upto the order of 10¹ S/cm. Temperature dependence verified metallic conduction and no metal-insulator transition was observed downto 7K.