Conducting polymers

Abstract

Polymeric materials, both synthetic and natural, are widespread and consequently familiar. These familiar materials are rarely simple; indeed, they encompass an enormous structural variety and complexity. They may be organic, inorganic or organometallic; they may consist of an assembly of discrete linear or branched molecules with a distribution of molecular sizes; or, at the other extreme, they may be virtually infinite three-dimensional networks; to complicate the picture yet further, some materials are constructed from a mixture of several structural types. Another layer of complexity arises from the fact that such materials are frequently formulated with the aid of a range of additives: fillers, plasticizers, pigments, anti-oxidants, stabilizers, and so on. The detailed properties of a particular material depend in a complicated way on a set of interacting factors, including molecular structure; molecular size and size distribution; cross-link density and its distribution; the conformation and ordering of the various components of the material; the chemical and physical history of the sample under consideration; and often on the time scale of the observation. Polymeric materials are only rarely molecularly monodisperse, some of the important biopolymers providing the only really notable exceptions to this generalization (1).