Anodic polymerization of thiophene derivatives from microemulsions and liquid crystals

Intrinsically conducting polymers (ICPs) of substituted thiophenes were obtained by anodic polymerization from microemulsions of the heterocyclic aromatic oils 3,4-ethylenedioxythiophene (EDOT) and 3-methoxythiophene (MOT) with high oil and nonionic surfactant content. A liquid crystal was polymerized for the first time allowing the formation of a free membrane in a platinum loop. Polymerization takes place under all conditions, but current transients and cyclovoltammograms yield a clear dependence of ICP properties on the composition of the microemulsion. Optimum conditions obtained for the polymerization current do not coincide with optimum redox properties. To understand these results, the multicomponent systems were characterized by phase behavior, conductivity, viscosity and dynamic light scattering. For microemulsions of EDOT, 0.5 M aqueous LiClO4 solution and a commercial alkyl polyethoxylate, a transition from the oil-in-water to the bicontinuous microemulsion was found at an oil content of about 45%. Continuous water domains exist up to a very high monomer content of more than 60% by weight. (C) 2001 Elsevier Science Ltd. All rights reserved.