Published online by Cambridge University Press: 15 March 2011
Reversible actuation strains in excess of 2% in the sheet direction and over 300% in the thickness direction have been produced by single wall carbon nanotube mats when electrochemically charged to +1.5V (vs. SCE) in aqueous sodium chloride solution. The observed strains represent a ten-fold increase over that previously reported for carbon nanotube actuators, and is considerably larger than that achievable with polymer ferroelectric actuators. The enhanced actuator strains result from a new mechanism of electrochemically induced “pnuematic actuation” where high pressure gas forms within the porous structure of the nanotube mat causing partial delamination and swelling. An erasable “memory” effect was also observed for pneumatic actuation driven by hydrogen gas evolution/storage in the nanotube electrodes.