The field of conductive polymers is one of the most exciting and innovative branches of polymer science today. These organic semiconductors have tremendous potential for applications in optical memory, electromagnetic shielding, aircraft, batteries, cable insulation, in photovoltaic and photoconductive diodes, solar energy converters and in field effect transistor devices. The advantage of conjugated polymers is that they are amenable to processing and device fabrication, which can make them significantly less expensive in production than the conventional alternatives. Scant progress in creating advanced polymer materials to date is related to their instability.

Polyacetylene is one of the most promising materials for applications in optoelectronics. The conductivity of this polymer after doping is equal to that of copper, and some forms of polyacetylene have record values of non-linear third-order optical susceptibility. The low stability of polyacetylene has been the major obstacle in the way of practical applications of this polymer. This instability has been attributed to the sensitivity of the polyene chain to defects.

In the first part of this review, the preparation of highly ordered polyacetylene blends is discussed. The author compares the forms of polyacetylene obtained by different methods. The review includes an analysis of the formation of defects in polyacetylene during growth of the polyene chain and cis-trans isomerisation. A model of acetylene polymerisation is described that relates the appearance of conformational defects in polyacetylene to the conditions of solid state formation. The mechanism of acetylene polymerisation with rhenium catalysts, and the reactivity of highly ordered polyacetylene blends to oxidation and doping are also discussed.

When acetylene is polymerised in solutions of certain saturated polymers, nanoparticles of polyacetylene are formed. The conditions required to produce this material are discussed in detail. These nanopolyacetylene blends appear to be stable, have a low defect content, and exhibit a set of unique optical properties, which are not characteristics of standard polyacetylene modifications. Studies of the electronic structure and optical properties of this highly ordered nanopolyacetylene are described, including the high intensity of Raman scattering, thermochromism and the transparency band in the optical spectrum in the near infrared field. Potential applications are outlined.

Dr Kobryanskii has been working in the field of conductive polymers for many years, and is a renowned expert on the subject of polyacetylene. He is based in Moscow, where much of the pioneering work on this topic has been carried out. This review will be of interest to those working to develop conductive polymers.

The review is supported by a fully indexed selection of over 400 references from the Polymer Library on the topic of polyacetylene.