Liquid crystal elastomers (LCEs) are a unique class of materials that combine rubber elasticity with liquid crystalline anisotropy to produce exceptional physical and optical properties such as actuation, soft elasticity, and birefringence. This review gives a brief overview of the physics behind liquid crystals and classifications of LCEs before discussing the methods traditionally used to synthesize LCEs, the new methods of synthesis that have emerged within the past several years, and the developing applications of LCEs. The review begins by discussing the organization of liquid crystals in LCEs and how their coupling to the polymer backbone affects their macroscopic properties. Traditional LCE synthesis methods and their drawbacks in terms of moving towards applications are then touched upon, as well as emerging chemistries that eliminate many of the challenges associated with LCE synthesis. Thiol-Michael reactions and covalent adaptable networks, which allow for bulk sample synthesis and repeated programming, respectively, are discussed at length. Finally, applications of LCEs in 4D printing and as biomedical devices are illustrated.

液晶弹性体（LCE）是一类独特的材料，它将橡胶弹性与液晶各向异性相结合，以产生出色的物理和光学特性，例如致动性，软弹性和双折射性。在讨论传统上用于合成LCE的方法，过去几年中出现的新合成方法以及LCE的发展应用之前，本文将简要概述液晶的物理原理和LCE的分类。本文首先讨论LCE中液晶的组织以及它们与聚合物主链的偶联如何影响其宏观性能。然后介绍了传统的LCE合成方法及其在走向应用方面的弊端，以及消除了许多与LCE合成相关的挑战的新兴化学方法。深入讨论了硫醇-迈克尔反应和共价适应性网络，它们分别允许批量样品合成和重复编程。最后，说明了LCE在4D打印中以及作为生物医学设备的应用。