Enhanced control and stability of polypyrrole electromechanical actuators

Abstract

The practical application of polypyrrole actuators requires a stable strain response and a high degree of reproducibility from sample to sample. The use of symmetrical voltage cycling to control the actuation of polypyrrole is shown to lead to a slow net oxidation of the polymer after several tens of cycles. The result is a slow deterioration in the actuation strain. The use of current pulsing reduces this problem and gives a more stable strain response. Current pulsing in combination with an ionic liquid electrolyte allowed a strain of 3% to be achieved repeatably for many different samples for at least 100 cycles.