Durham poly acetylene: preparation and properties of the unoriented material

Polyacetylene prepared by the Shirakawa route is a mat of crystalline fibrills, which are capable of being oxidized or reduced to a highly conducting state. Polyacetylene can also be produced from a soluble precursor polymer by a thermally driven transformation reaction (the ‘Durham’ route) as a solid, coherent film. This transformation consists of the elimination of a substituted benzene unit followed by the isomerization of the largely cis polyacetylene produced to a disordered trans isomer. We have studied the effect of different transformation conditions and from these studies it is possible to gain an insight into these processes. Techniques such as caloremetry, infrared, resonance Raman and optical spectroscopy, e.s.r., X-ray diffraction and electrical conductivity have all been used to probe the transformation and the product. The resultant information gives a consistent picture of the overall transformation processes detailed above but also shows an ordering associated with higher transformation temperatures. A thorough knowledge of these processes enables the orientation of the precursor to produce highly crystalline material.