Structure and Electroconductivity of a Sheared Liquid-Crystalline Polyacetylene Derivative: Poly(5-p-(trans-4-pentacyclohexyl)phenoxy-1-pentyne)

The crystal structure of the compound 5- p -( trans -4-pentacyclohexyl) phenoxy-1-pentyne (PCH503A) was determined by X-ray diffraction. The structure and orientational behavior of the polymer (PPCH503A), prepared from the monomer compound, was examined. As a result, it was found that the polymers form an alternating comblike conformation of side chains and are stacked into a smectic hexagonal structure. When shear stress was applied to the polymers, polymeric chains were oriented with their axes of mesogenic groups parallel to the shearing direction; that is, the polymer backbones were aligned perpendicular to the shearing direction. The oriented polymer exhibited a high anisotropy of electroconductivity, i.e., σ ∥ (the electroconductivity parallel to the backbone) became 1.7 × 10 -5 S/cm upon doping iodine, and the ratio of σ ∥ to σ ⊥ (the electroconductivity perpendicular to the backbone) was about 10.