Conducting polymer soft actuators based on polypyrrole films—energy conversionefficiency

Abstract

The electrochemomechanical deformation (ECMD) of conducting polymers can be usedto create soft actuators or transducers for the conversion of electric power tomechanical work. Polypyrrole (PPy) films, which were electrodeposited from amethyl benzoate solution of tetrabutylammonium (TBA) trifluoromethansulfonate,TBACF3SO3, were used to investigate the energy conversion efficiency. The films are known to havehigh tensile strength and to produce large strain at high stress in ECMD. The current asa function of load stress under constant applied potentials versus a referenceelectrode was studied in various electrolytes. Reduction currents increased withincreasing load stress for contraction of the film (lifting weights) as well as for theoxidation current (expansion), indicating that the electrical input was sensing theload hung on the actuators. During the contraction, the conversion efficiency wasestimated from the mechanical work energy. The maximum work energy-per-cycle was140 kJ m−3. It has been found that the energy conversion efficiencies are very small(<0.25%). Most of the input electrical energy is stored electrochemically, but a significant fraction isalso dissipated.