Dual‐Responsive MXene‐Functionalized Wool Yarn Artificial Muscles

Abstract Fiber‐based artificial muscles are promising for smart textiles capable of sensing, interacting, and adapting to environmental stimuli. However, the application of current artificial muscle‐based textiles in wearable and engineering fields has largely remained a constraint due to the limited deformation, restrictive stimulation, and uncomfortable. Here, dual‐responsive yarn muscles with high contractile actuation force are fabricated by incorporating a very small fraction (<1 wt.%) of Ti 3 C 2 T x MXene/cellulose nanofibers (CNF) composites into self‐plied and twisted wool yarns. They can lift and lower a load exceeding 3400 times their own weight when stimulated by moisture and photothermal. Furthermore, the yarn muscles are coiled homochirally or heterochirally to produce spring‐like muscles, which generated over 550% elongation or 83% contraction under the photothermal stimulation. The actuation mechanism, involving photothermal/moisture‐mechanical energy conversion, is clarified by a combination of experiments and finite element simulations. Specifically, MXene/CNF composites serve as both photothermal and hygroscopic agents to accelerate water evaporation under near‐infrared (NIR) light and moisture absorption from ambient air. Due to their low‐cost facile fabrication, large scalable dimensions, and robust strength coupled with dual responsiveness, these soft actuators are attractive for intelligent textiles and devices such as self‐adaptive textiles, soft robotics, and wearable information encryption.