COUPLING ORDER AND CONDUCTIVITY LIQUID-CRYSTALLINE CONJUGATED POLYMERS

Acetylenic and diacetylenic liquid crystalline monomers have been prep ared in order to obtain conjugated polymers with an orientational char acter. Unlike the polydiacetylene derivatives obtained and which do no t exhibit any mesomorphic behaviour, a smectic phase, stable over a la rge temperature range, occurs in the case of all the polyacetylenes. T his mesophase appears to be stabilized by an in situ polymerization of the monomers oriented in the nematic state. After iodine doping, a ne matic phase appears in the polymer in addition to the smectic phase. A C complex conductivity measurements, realized over a large frequency r ange. are reported for some doped and undoped polyacetylenes. Prelimin ary results concern both non-oriented polymers and an undoped polymer in which the mesogenic groups have been oriented after polymerization.