Performance and work capacity of a polypyrrole conducting polymer linear actuator

This paper reports a performance analysis of a conducting polymer film actuator made of polypyrrole (PPy). Electrochemomechanical characterizations of the active displacement and the developed force of a PPy free-standing film at different loading conditions are performed. Two driving signals are used: the former, a cyclic voltammetry at 1 mV/s between +/-1 V, is used to carry out an accurate on-line analysis of the film displacement; the latter, a current square wave between 0.02 and 0.1 Hz, is helpful for evaluating the effectiveness of the actuator in terms both of actuation strain and of developed force. The experimental results indicate that 1% displacement, 3 MPa force and working density of 73 kJ/m(3) are achievable goals for a conducting polymer linear actuator, which are interesting results if compared with the limiting specifications of skeletal muscle. Additionally, two different approaches to the electrochemomechanical modeling of the conducting polymer-fluid electrolyte system are illustrated, together with a discussion about foreseen improvements in the implementation of actuating structures. (C) 1997 Elsevier Science S.A.