Enhancement actuation mechanism for the sheath-run artificial muscle fiber under weak current

Electrothermal sheath-run artificial muscles hold great promise for various applications. Their sheath expands and softens when subjected to Joule heat generated by high currents, effectively releasing the stored torsional energy within the core fiber. This phenomenon significantly enhances actuation performance. In this study, an artificial muscle composed of pre-twisted carbon nanotube (CNT) fiber encased in polydimethylsiloxane (PDMS) sheath was prepared. Under a 50-mA current at a frequency of 0.25 Hz, it demonstrated a 13.28