Enabling High‐Performance Artificial Muscles via a High Strength Fiber Reinforcement Strategy

Abstract Coiled‐polymer‐fiber‐based artificial muscles can provide large contractile actuation stroke. However, it is a challenge to achieve high actuation load and high actuation stroke for artificial muscle simultaneously. Herein, a powerful coiled‐polymer‐fiber‐based artificial muscle with a “rigid‐and‐flexible” structure is fabricated by cotwisting rigid heterocyclic aramid (HA) fibers with flexible silver‐plated nylon (SPN) fibers. The artificial muscle based on coiled HA@SPN fibers can lift a load over 108 MPa with a fast response time of 0.6 s, which is 309 times heavier than the load that human muscle can lift, and generate a work density per temperature of 41.3 J (kg °C) −1 . The coiled HA@SPN fiber muscle exhibits high actuation stability of over 30 000 cycles. The coiled HA@SPN fiber muscle can provide a contractile actuation stroke of up to 8.2% and generate an average gravimetric mechanical energy density of 702 J kg −1 , which is 18.1 times that of human skeletal muscle (≈38.8 J kg −1 ). An average contractile power density of 1168 W kg −1 is obtained for coiled HA@SPN fiber muscle, which is 23.4 times that of human skeletal muscle (≈50 W kg −1 ).