High performance conducting polymer actuators utilising a tubular geometry and helical wire interconnects

Electromechanical actuators based on conducting polymers can be viewed as simple electrochemical cells in which the application of a potential creates dimensional changes in one or more of the electrode materials. The ability to efficiently inject/extract charge without mechanical degradation of the system determines the overall performance possible. It is obvious then that the electrochemical properties of the active component(s) will dictate the level of performance attainable. In most devices with dimensions greater than microns, performance is limited by the electrical connection made to the device. In this work, a thin helical wire interconnect has been used in the construction of tubular electromechanical actuators based on polypyrrole. The interconnection results in greater strain (up to 5%) and strain rates (in excess of 10% s(-1)) when the actuator is used in the axial strain mode. (C) 2002 Elsevier Science B.V. All rights reserved.