The Preparation of Polyacetylene.

Polyacetylene CHx, is a simple organic polymer with a linear conjugated unsaturated structure. It can exist in two forms, cis and trans. CHx is almost entirely cis when synthesized at 77 K, the cis-trans ratio decreasing when the temperature is raised until isomerization to trans-CHx is complete at about 150 C. The polymer can be produced as a thin film or a flocculent precipitate and consists of randomly oriented fibrils about 200A in diameter. Pristine CHx is an insulator, but when chemically doped, its conductivity approaches that of the metals. It has been proposed as a component in Schottky diodes and solar cells and it has potential as the cathode in polymer-electrode batteries. Films of CHx doped with Li, C104- and CF3SO3- have been used as the anode and cathode in electrochemical cells employing a polyethylene oxide-complex electrolyte and also in non-aqueous liquid electrolyte cells. Flocculent CHx is produced by bubbling acetylene gas through a catalyst solution, but as films were required for the battery studies associated with this work, a variation of the Shirakawa process was employed. In this method, purified acetylene is admitted into an evacuated reaction vessel containing dissolved catalysts at low temperature. The films formed are removed in a controlled atmosphere box. The details of this method are described in this report.