Development of low-temperature driven high-strength interpenetrating polyurethane-liquid crystal elastomer actuators with self-sensing property

Actuators based on thermotropic liquid crystal elastomers (LCEs) with excellent reversible deformations have broad applications in soft robotics, micro and nano devices, and bionic manufacturing. However, these components suffer from sharp mechanical properties degradation at phase transition temperatures. Herein, the breaking strength of the LCE at the anisotropic–isotropic transition temperature ( T ni = 53.8 ℃) is increased, by an order of magnitude, by introducing a high-temperature resistant, high modulus, and self-healing crosslinked polyurethane network designed for the molecular chain network of the actuator. The developed actuator can lift an object 800 times its own weight with a contraction ratio of 40.6 %, and the object can be lifted up to 2000 times. The actuation performance was stable during the reciprocating test, and the damaged actuator could still restore 88.7 % of actuation performance and 60.4 % of the mechanical property after self-healing. Furthermore, a self-sensing characteristic was conferred by the carbon nanotube/carbon black composites (CNT/CB)-modified porous structure constructed on the surface. The actuator developed with a low actuation temperature, excellent actuation performance, self-healing, and self-sensing is expected to expand the applications of LCEs.