Dense carbon nanotube array-ionic electroactive polymer composite actuators

Abstract

We developed an ionic electroactive polymer-based actuator integrating a Nafion and carbon nanotube (CNT) composite electrode material. The electrodes are composed of high-density, closely packed arrays of vertically-aligned CNTs on a current collector and are oriented perpendicularly to the plane of the membrane. The CNTs act as high-surface-area scaffolding for the impregnated Nafion ionomer layer. The increased electroactive area improves the force generation and provides a similar degree of bending deformation to neat Nafion actuators. An ionic liquid electrolyte (1-ethyl-3- methylimidazolium tetrafluoroborate) was incorporated to further enhance the actuation and force. The CNT composite actuators produced between two and ten times the force compared to commercially available materials. The degree of deformation was comparable to neat Nafion actuators. The actuators consumed approximately 500 μA at 4 VDC, a power draw of 2 mW.