Electrothermally-Driven Elongating-Contracting Film Actuators Based on Two-Way Shape Memory Carbon Nanotube/Ethylene-Vinyl Acetate Composites

Electrothermally-driven shape-memory composites (EDSMCs) are promising candidates in the field of actuators; however, they are still unable to deliver both substantial stretching strain and precise strain control, which limits their potential applications. A carbon nanotube (CNT) EDSMC composite made from ethylene-vinyl acetate (EVA) is fabricated in this study using a novel hot-pressing and xylene-aided ultrasonic adsorption two-step procedure to overcome this problem. Because of the outstanding electrical response of the CNT/EVA EDSMC, even at 50% tensile strain, it can accomplish electrothermally-driven melting-induced contraction (an extraordinary working limit for shape memory polymers-based actuators). A large reversible strain and precise strain control can be integrated simultaneously with crystallization-induced elongation at different cooling time. In addition, programmable actuation behaviors are made possible by the CNT/EVA EDSMC, which can generate predictable and diverse strain changes. Furthermore, the lightweight CNT/EVA EDSMC demonstrates good load capacity and can lift an object to 1000 times its weight. The CNT/EVA EDSMC shows durable performance under repeated elongation and contraction cycles tests over 100 times, without significant reduction of the strain precision, and had broad prospects for both engineering devices and robotics.