Stimuli‐Responsive Liquid Crystal Elastomers: From Materials to Applications

Abstract Liquid crystal elastomers (LCEs) are well‐known for their significant, reversible, and anisotropic shape changes when exposed to different external stimuli due to their crosslinked polymer networks that merge the elastic properties of rubbers with the anisotropic characteristics of liquid crystals. LCEs with stimuli‐responsive behaviors are preferable for applications in robotics, bio‐medics, electronics, optics, and energy. In this review, the state‐of‐the‐art advances in stimuli‐responsive LCEs are reviewed, including thermo‐responsive LCEs, photo‐responsive LCEs, electro‐responsive LCEs, and other responsive LCEs, such as chemical‐responsive LCEs, magnetic‐responsive LCEs, humidity‐responsive LCEs, radio‐frequency‐responsive LCEs, ultrasonic‐responsive LCEs, and photothermal‐responsive LCEs, all of which have contributed to the resurgence in LCE research. The LCEs exhibit remarkable performance, spanning several orders of magnitude. They typically achieve actuation strains of 5–500%, stresses of 0.01–20 MPa, and fast response speeds, making them promising systems for actuators and artificial muscles. Furthermore, the applications of these responsive LCEs in information encryption, force sensors, and material transportation are demonstrated, which have significant potential for further development of the next‐generation advanced functional materials. Finally, this review concludes with a summary and perspective on the current challenges and emerging research opportunities for high‐performance LCEs endowed with remarkable properties.