Anisotropic electrical conductivity of drawn elastomeric ionene–TCNQ salts

Abstract

AbstractElastomeric ionene–TCNQ salts with favorable electrical, mechanical, and processing characteristics were drawn mechanically. The electrical conductivity parallel and perpendicular to the drawing axis was investigated. Correlation between anisotropic conductivity and the change in microstructure was discussed. The resistivity ρ at 25°C of the simple salt (EI‐TCNQ0) and the complex salt (EI‐TCNQ0.5) were on the order of 105 and 102 Ω cm, respectively. In the drawn TCNQ salts, the ρ parallel to the drawing axis increased greatly; on the other hand, the ρ perpendicular to this axis increased slightly or was similar to the ρ of the undrawn TCNQ salts. The anisotropy in the ρ of EI‐TCNQ0.5 between the two directions reached 40 times. The activation energy also increased in the direction parallel to the drawing axis. In the undrawn TCNQ salts, the continuous conduction paths exist isotropically. With drawing, the continuous conduction paths, particularly in the direction parallel to the drawing axis, break or make a structural change. The anisotropic conductivity disappeared with time in EI‐TCNQ0; however, it was present in EI‐TCNQ0.5 even after 200 days under ambient conditions.