An arm-like electrothermal actuator based on superaligned carbon nanotube/polymer composites

A superaligned carbon nanotube film embedded in polymers shows promising applications in the fields of electrothermal actuation because of their homogenous conductivity, good biocompatibility and mechanical properties. We fabricated a simple U-shaped gadget from the composite to investigate the electrothermal actuation mechanism. The gadget can curl to 730°, which is several times larger than existing actuators. A helix-shaped arm-like actuator (artificial arm) was also made from the composite, which exhibited a large twisting deformation (more than 700° twisting, 49.2% length constriction and 26.4% diameter constriction) when driven with low electrical fields (less than 500 V/m or 41 V). The actuation of the U-shaped gadget and the artificial arm can be precisely controlled by the applied voltage or electrical power. The gripping force of the clenched arm is about 4 g, 26 times its own weight. This points to a new way for manipulating objects and its potential application in the biomimetic field.