Liquid crystal elastomers for actuation: A perspective on structure-property-function relation

Liquid crystal elastomers (LCEs) have long held significant promise as materials for artificial muscles and smart actuators. Recent advancements in this field have introduced innovative LCE structures at various scales, resulting in novel properties and functionalities that further accentuate their actuation advantages, bolstering their potential as future soft actuation systems. The ongoing pursuit of enhanced performance and functionality in LCE actuators, essential for advancing them towards superior material-based machines and devices, is intricately linked to the understanding of the fundamental structure-propertyfunction relationships. This review provides a perspective on these relationships across multiple structural levels, encompassing chemical structures, mesophase structures, and micro-to-macroscale programmed structures. It delves into the impact of various LCE structures on key actuation-related properties, actuation features, and functionalities. This review aspires to provide valuable insights into the design of high-performance LCE actuators, the development of exceptional actuation modes and behaviors, and the expansion of achievable functionality.