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Keywords:

  • actuators;
  • carbon;
  • ionic liquids;
  • nanotubes;
  • redox chemistry

Abstract

Actuators with a high-speed response under a high-frequency (more than 100 Hz) applied square-wave voltage of ±2 V have been developed with an electrode composed of millimeter-long single-walled carbon nanotubes synthesized by the “supergrowth method” (SG-SWNTs) and ionic liquids (ILs). Detailed studies concerning induced electric current and transferred charge in the electrode as well as cyclic voltammetric studies of the electrode revealed that the high-speed response originates from the electric current generated by an oxidation/reduction (redox) reaction in addition to electric double-layer charging. The contribution of the redox reactions of SG-SWNTs to the actuation is sensitive to the presence of supporting polymers, the thickness of the electrolyte, and the amplitude of the applied voltage.