Novel Doping Effect of Conducting Polymer Gel

Abstract

The volume of conducting poly(3-alkylthiophene) gel shrinks drastically upon doping and recovers upon undoping. With decreasing temperature below some threshold, the volume of undoped poly(3-alkylthiophene) get decreases remarkably but the change in the volume of doped gel is nearly negligible. The color of poly(3-alkylthiophene) gel changes from yellow in the undoped expanded state to red in the undoped shrunken state and also to black in the doped shrunken state. The conductivity of poly(3-alkylthiophene) gel reaches about 10^-1 S/cm upon iodine doping. This enhancement of conductivity is more remarkable in the shrunken state in the poor solvent. The application of these phenomena to a molecular actuator has been proposed.