Highly conductive and stiff fibres of poly(2,5-dimethoxy- p-phenylenevinylene) prepared from soluble precursor polymer

Abstract

Fibres of poly(2,5-dimethoxy- p-phenylenevinylene), PDMPV, were prepared from a precursor polymer, poly[2,5-dimethoxy- p-phenylene (1-methoxyethylene)] which is soluble in organic solvents. Wet-spun precursor polymer fibres were drawn and converted to PDMPV in a temperature-controlled, continuous drawing system. X-ray diffraction patterns of the drawn PDMPV fibres indicated a high degree of molecular orientation with a mosaic spread less than 8°. Tensile drawing of PDMPV resulted in a dramatic improvement of the mechanical properties; at a draw ratio of 8, the modulus and strength were 35 GPa and 0.7 GPa, respectively. After doping (with iodine), the PDMPV fibres became highly conducting ( σ = 1200 S cm −1) while retaining excellent mechanical properties: the modulus decreased to 25 GPa and the tensile strength remained essentially unchanged. A strong correlation between the electrical conductivity and the mechanical properties was found.