Organic metals and semiconductors: The chemistry of polyacetylene, (CH)x,and its derivatives

Polyacetylene, (CH)_x, is the simplest organic polymer. Both the cis- and trans-forms may be prepared as silvery, flexible, polycrystalline, semiconducting films. The cis-films can be stretched to over three times their original length with partial alignment of the (CH)_x fibrils. Through chemical or electrochemical doping, the electrical conductivity of the films can be increased over twelve orders of magnitude with properties ranging from insulator (σ < 10^?10 ohm^?1 cm^?1) to semiconductor, to metal (σ > 10³ ohm^?1 cm^?1). By the use of donors or acceptors, n-type or p-type polymer, respectively, is produced. When doped, the partly aligned (CH)_x film shows marked anisotropic electrical and optical properties. The more chemically oriented aspects of (CH)_x and its derivatives and those physical studies which are most illustrative of the effects of doping will be discussed.