Conducting polymer soft actuators based on polypyrrole films—energy conversion efficiency

• Published in: Smart materials and structures Vol. 16; no. 2; pp. S250 - S255
• Main Authors: Kaneto, Keiichi, Fujisue, Hisashi, Kunifusa, Masakatsu, Takashima, Wataru
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2007
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/16/2/S08

The electrochemomechanical deformation (ECMD) of conducting polymers can be used to create soft actuators or transducers for the conversion of electric power to mechanical work. Polypyrrole (PPy) films, which were electrodeposited from a methyl benzoate solution of tetrabutylammonium (TBA) trifluoromethansulfonate, TBACF3SO3, were used to investigate the energy conversion efficiency. The films are known to have high tensile strength and to produce large strain at high stress in ECMD. The current as a function of load stress under constant applied potentials versus a reference electrode was studied in various electrolytes. Reduction currents increased with increasing load stress for contraction of the film (lifting weights) as well as for the oxidation current (expansion), indicating that the electrical input was sensing the load hung on the actuators. During the contraction, the conversion efficiency was estimated from the mechanical work energy. The maximum work energy-per-cycle was 140 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 is also dissipated.