Zone-reacted poly(p-phenylene vinylene) films. Changes in mechanical properties and microstructure by acid doping

The doping of highly oriented poly(p-phenylene vinylene) films prepared by the zone-reaction method was performed with various acids, HCl, H2SO4, and H3PO4. The changes in the microstructure, electrical, tensile, and viscoelastic properties of the resulting films were studied. It was found that the doping of HCl and H2SO4 increased the electrical conductivity to 186 and 61 S cm−1 at the doping time of 6 and 1.5 h, respectively. A further doping, however, lowered the conductivity, which was associated with the relaxation of molecular orientation. The zone-reacted film doped with HCl preserved Youngʹs modulus and tensile strength as high as 44.7 and 0.73 GPa, where dynamic storage modulus was 49 GPa at 25 °C and held 21 GPa at 400 °C.