Large-deformation, multifunctional artificial muscles based on single-walled carbon nanotube yarns

Light-weight, strong, and conductive carbon nanotube yarns have demonstrated many applications as supercapacitor and solar cell electrodes, electrical wires, actuators, and sensors. In particular, nanotube yarns can serve as multifunctional electrochemical or electromechanical actuators with large stroke, fast response, and fatigue resistance. The helical yarn is also super-stretchable, and can maintain reversible stress response to voltage pulses when it is stretched to very high tensile strains. Compared with previous MWNT yarn actuators, the ultra-flexible SWNT yarns are made from single-walled nanotubes, can generate large deformation in various configuration and also work at large tensile strains. the wax only enters the inside part of each loop without filling and connecting the gaps, which otherwise may prevent loop separation and lose stretchability. On the other hand, the yarn surface has been filled by wax, showing a different morphology compared with initial porous yarns.