%0 Journal Article %J Smart Mater. Struct. (UK) %D 2007 %T Electrochemical actuation of carbon nanotube yarns %A Mirfakhrai, T %A Oh, Jiyoung %A Kozlov, M %A Fok, E C W %A Zhang, Mei %A Fang, Shaoli %A Baughman, R H %A Madden, J D W %K carbon nanotubes;electric actuators;tensile strength; %P 243 - 9 %U http://dx.doi.org/10.1088/0964-1726/16/2/S07 %V 16 %X We report on actuation in high tensile strength yarns of twist-spun multi-wall carbon nanotubes. Actuation in response to voltage ramps and potentiostatic pulses is studied to quantify the dependence of the actuation strain on the applied voltage. Strains of up to 0.5% are obtained in response to applied potentials of 2.5 V. The dependence of strain on applied voltage and charge is found to be quadratic, in agreement with previous results on the actuation of single-wall carbon nanotubes, with the magnitude of strain also being very similar. The specific capacitance reaches 26 F g-1. The modulus of the yarns was found to be independent of applied load and voltage within experimental uncertainty %Z electrochemical actuation;carbon nanotube yarns;high tensile strength yarns;twist-spun multiwall carbon nanotubes;voltage ramps;potentiostatic pulses;single walled carbon nanotubes;2.5 V; %9 article