DURHAM ROUTE TO POLYACETYLENE.

The Durham route to polyacetylene is through a non-conjugated and soluble precursor polymer which by a simple thermal elimination reaction gives polyacetylene and a volatile aromatic leaving group. The precursor route that we have studied most is illustrated, but several other precursor polymers, with different leaving groups, have also been synthesised, and these allow further selection of the conditions for the elimination reaction. Polyacetylene prepared by the Durham route is fully dense, and bulk chemical doping of polyacetylene films is therefore slower than for Shirakawa polyacetylene. The films can be obtained in a range of forms. Unstructured films show little crystallinity and short sequences of straight chain, whereas films that are stretched during the transformation reaction can be highly-oriented, exhibiting a high degree of crystallinity, and showing evidence, from Raman ESR and conductivity experiments for longer straight-chain lengths.