Polymers with Metal‐Like Conductivity—A Review of their Synthesis, Structure and Properties

Abstract Polymers such as polyacetylene, which have an extended π‐electron system in their backbone, or like poly( p ‐phenylene) consist of a sequence of aromatic rings are excellent insulators in their native state and can be transformed by oxidation or reduction in the solid state into conductive CT‐complexes which exhibit metal‐like conduction characteristics. The chemical and physical processes involved and the reasons for the observed quasimetallic conductivity are not yet fully understood. The real structure of these materials in chemical and physical terms, i. e. their complicated morphology and texture, as well as the results available on the structure‐property relationships of the “organic metals” must be considered when discussing their properties. In other words, a discussion of conductive polymers should be based on what is known of the highly conducting CT‐complexes of low‐molecular weight compounds. The discovery of the highly conducting polymer complexes has opened up a new interdisciplinary field of research which borders on polymer science, solid‐state and semiconductor physics and on organic solid‐state chemistry. It is hoped that this area will lead to numerous novel materials and technical applications.