Recent advances in the design, fabrication, actuation mechanisms and applications of liquid crystal elastomers

Liquid crystal elastomers (LCEs), as an intriguing class of soft active materials, exhibit excellent actuation performances and biocompatible properties, as well as a high degree of design flexibility, which have been of increasing interest in many disciplines. This review summarizes recent developments in this inspiring area, providing an overview of fabrication methods, design schemes, actuation mechanisms, and diverse applications of LCEs. Firstly, two-stage and one-pot synthesis methods, as well as emerging fabrication techniques (e.g., 3D/4D printing and top-down microfabrication techniques) are introduced. Secondly, the design and actuation mechanisms are discussed according to the different types of stimuli (e.g., heat, light, and electric/magnetic fields, among others). Thirdly, the representative applications are summarized, including soft robotics, temperature/strain sensors, biomedical devices, stretchable displays, and smart textiles. Finally, outlooks on the scientific challenges and open opportunities are provided.