Reprogrammable 3D Liquid‐Crystalline Actuators with Precisely Controllable Stepwise Actuation

Liquid‐crystalline elastomers (LCEs) are considered ideal soft actuator materials for a wide range of applications, especially the thriving soft robotics. However, 3D LCE actuators capable of precisely controllable stepwise actuation, which can enhance functionality and versatility of LCE robots for multifarious complicated applications, are still in urgent need for the reported LCE actuators mainly exploit the one‐step actuation upon the liquid‐crystallin (LC)‐isotropic phase transition temperature (Ti). Herein, a catalyst‐free LC‐vitrimer actuator with supercritical behavior is designed, which can perform precisely controllable stepwise actuation with extraordinary shape stability over a broad temperature range of about 70 °C. Moreover, supercritical behavior enables the actuator to be used in nematic phase, imparting the actuator with some extra advantages, such as higher mechanical strength and actuation stability, over the one used above Ti. Furthermore, the LCE can be reprogrammable into arbitrary 3D actuators, which can further be integrated into single‐material actuators with complex stepwise actuation, offering a generalized strategy of LCE actuators for sophisticated practical soft robots.