The amounts per cycle of polypyrrole electromechanical actuators

The energy output (work) generated by polypyrrole actuators has been determined from the actuator strain operating against a constant force. The strain decreases as the force increases leading to a maximum in the amounts per cycle at an intermediate force. The behaviour agrees well with previous analyses (Baughman 1996 Synth. Met. 78 339–53). The amounts per cycle depends upon the applied electrical stimulation and on the actuator geometry. Flat films were found to be inferior to hollow tubes, which, in turn, were inferior to similar tubes containing a helical platinum wire in the tube wall. A maximum work capacity of 83 kJ m−3 was determined for the helix tubes, which is the highest reported work capacity of polypyrrole actuators.