Woven Coiled Nylon Artificial Muscles with Large Tensile Stress and High Stability

Abstract

Artificial muscles have a wide range of potential applications and can be fabricated by using a variety of materials. To meet the demands of various applications, artificial muscles must exhibit excellent performance characteristics, such as a large contraction stroke, high contraction stress, and long cycle life. Here, we report a coiled nylon fiber artificial muscle and a triple-braided nylon fiber (TBNF) artificial muscle, which are prepared by the weaving method for twisted nylon fiber. Driven by Joule heating, the TBNF demonstrates excellent actuation properties, including 10.2% tensile stroke, 527.8 J/kg work capacity, and 9600 stable cycles. Moreover, the TBNF muscle can generate a reversible tensile stress of 5.85 MPa, which is 20 times that of human skeletal muscle. The TBNF muscles are demonstrated to drive a robotic car movement and bionic skeletal actions such as lifting weights and moving legs. In addition, due to the contraction driven properties of the TBNF muscle, it can be applied in microcurrent switches to control lighting. Consequently, electrothermally driven nylon fiber artificial muscles have significant applications in bionic robotics, prosthetic exoskeletons, and beyond.