D.c. conductivity of some linear conjugated polymers

Abstract

A variety of polymers and copolymers have been formed from substituted acetylenes and the d.c. conductivity measured. The substituent groups were of varying electrophilic and nucleophilic character in order to facilitate inter-chain conduction. Unfortunately, the polymers do not, of themselves, form materials of abnormally large conductivity. The formation of charge-transfer complexes increases the conductivity, but not above values reported for low molecular weight materials or non-conjugated polymers. It is suggested that the adoption of different chain conformations will always limit the conjugation length to a value less than the chain length. The spectral and electrical properties of these polymers can be rationalized in terms of this model, and a quantitative example is included.