Thermally Responsive Torsional and Tensile Fiber Actuator Based on Graphene Oxide

Graphene-based actuators are of practical interest because of their relatively low cost compared with other nanocarbon materials, such as carbon nanotubes. We demonstrate the simple fabrication of graphene oxide (GO)-based fibers with an infiltrated nylon-6,6 polymer by wet spinning. These fibers could be twisted to form torsional actuators and further coiled to form tensile actuators. By controlling the relative twisting and coiling direction of the GO/nylon fiber, we were able to realize reversible contraction or elongation actuation with strokes as high as -80 and 75%, respectively, when the samples were heated to 200 °C. The tensile actuation showed a remarkably little hysteresis. Moreover, this GO/nylon actuator could lift loads over 100 times heavier than itself and generate a stable actuation at high temperatures over the melting point of the polymer. This novel kind of GO-based actuator, which has a multidirectional actuation, has potential for a wide range of applications such as artificial muscles, robotics, and temperature sensing.