Actuators based on steric effect from cation insertion and extraction

The novel features of electrochemical actuators fabricated from a cylindric al polypyrrole (PPy) pipe prepared by the electrochemical polymerization te chniques have been described. This cylindrical PPy pipe was cut into a rect angular film and its electrochemical and electrical properties were measure d. When the inner surface of the PPy film (surface in contact with electrol yte when PPy was polymerized) was insulated and redox was carried out, the PPy film bent toward the outer surface (surface in contact with a slender T eflon pipe when PPy was polymerized) upon reduction and returned to its ori ginal shape upon oxidation. However, the bending was not completely accompl ished by redox when the outer wall side of the PPy film was insulated. Alth ough such an anomalous bending in the PPy film actuator cannot be explained satisfactorily at this stage, we speculate that the bending phenomena are due to steric effects from cation insertion and extraction.