Polythiophene and polythiophene-based conducting composites

Abstract

Conducting polythiophene and conducting polymer composites containing polythiophene are prepared. A one-step oxidative reaction of 2,2′-bithiophene with one of the following oxidants, copper perchlorate hydrate, iron perchlorate hydrate, ferric chloride or ferric chloride hydrate, in a suitable solvent produces a doped polythiophene, the conductivity of which reaches values as high as 4.5 S/cm. The conducting polymer composite is based on a highly porous crosslinked polystyrene as host polymer. It was prepared by imbibing the host polymer with a monomer solution, partially drying the saturated host polymer and imbibing again with an oxidant solution for polymerization to occur. The composites, particularly those prepared using ferric chloride as initiator and dopant, are environmentally stable reach conductivities as high as 4.8 S/cm. The conductivity of the composite is influenced by the type of oxidant and the initial concentrations of oxidant and monomer. The IR spectra of the doped polythiophene provide evidence that both the oxidative reaction and doping occur in the one-step reaction. SEM micrographs of the composites show that polythiophene coats uniformly the inside of the porous host polymer.