Table 1 Actuation mechanism and performance of fiber type, torsional artificial muscles
Stimuli | Material | Structure | Torsional Stroke (°/mm) | Peak Torsional Speed (rpm) | Work capacity (J/kg) | Torque-to-mass ratio (N.m/kg) | Ref |
|---|---|---|---|---|---|---|---|
Electric field | CNT/ Rubber | Twisted | 4.44 | Â | Â | Â | |
Electrochemical | CNT | Twisted | 52 | Â | Â | Â | |
CNT | Two-end–tethered, twisted |  | 590 |  |  | ||
CNT/PSS | Two-end–tethered, twisted | 6.4 | 150-200 |  | 0.89 | ||
Electro-thermal | NiTi alloy | Two-end–tethered, twisted | 16 | 10500 | 8 ~ 10 | 8 | |
Solvent vapor | PEO-SO3/CNT | Sheath-core | 143 | 507 | Â | Â | |
CNT | Twisted | 447.5 | 2050 | 26.7 | 0.63 | ||
Thermal | LCE | Twisted | 243.6 | 2400 | Â | 10.1 | |
|  | CNT/Polymer | Two-end–tethered, twisted | 60 | 11500 |  | 8.42 | |
| Â | Graphene Oxide/Nylon | Twisted | 14.85 | Â | Â | Â | |
Moisture | Â | Â | Â | Â | Â | Â | Â |
Viscose/PET | Sheath-core | 581.5 | Â | 23.5 | Â | ||
Silk | Twisted | 547 | 975 | Â | 0.063 | ||
Spider silk | Nontwisted | 255 | 5.83 |  | 7.59 × 10^-4 | ||
Lotus fiber yarn | Twisted | 200 | Â | 0.488 | Â | ||
Human hair | Twisted | 104 | Â | 6.35 | Â | ||
Magnetic | CNT | Two-end–tethered, twisted | 0.79 |  |  | 8.42 | |
Light | Graphene Oxide/ Sodium Alginate | Twisted | Â | 500 | Â | Â |
