Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
J Mater Chem B. 2020 Aug 12;8(31):6610-6623. doi: 10.1039/d0tb00754d.
Liquid crystal elastomers (LCEs) have recently shown great potential in the applications of soft robotics, biomedical devices, active morphing structures, self-regulating systems and biomimetic demonstrations. Physical properties of LCEs highly depend on their crosslinking and the alignment of mesogens in the polymer network. Different strategies have been adopted to control and program the alignment of mesogens in LCEs over the recent decades, including stretching a loosely crosslinked LCE during its second-step crosslinking reaction, application of a strong magnetic or electrical field onto an LCE during its crosslinking process, and crosslinking a LCE thin film on the top of a surface with predesigned molecular texture. In the most recent decade, dynamic covalent bonds, which can undergo exchange reactions with or without external stimuli, have been introduced into LCEs to enable facile programing of mesogen orientation in the elastomer. In addition to the programmability, the LCEs with dynamic covalent bonds have also shown great recyclability, self-healing abilities and reprogrammability. In this article, we will review the recent progress in the synthesis, programming and application of LCEs with dynamic covalent bonds. We will also discuss the challenges and research opportunities in the field.
液晶弹性体（LCEs）在软机器人、生物医学设备、主动变形结构、自调节系统和仿生演示等应用中显示出巨大的潜力。LCE 的物理性质高度依赖于其交联和介晶在聚合物网络中的排列。在过去的几十年中，已经采用了不同的策略来控制和编程 LCE 中介晶的排列，包括在第二步交联反应期间拉伸交联程度较低的 LCE、在交联过程中对 LCE 施加强磁场或电场、以及在具有预定分子纹理的表面上交联 LCE 薄膜。在最近十年中，引入了可与或不与外部刺激发生交换反应的动态共价键，以实现弹性体中介晶取向的简便编程。除了可编程性之外，具有动态共价键的 LCE 还表现出良好的可回收性、自修复能力和可重编程性。本文综述了具有动态共价键的 LCE 的合成、编程和应用的最新进展。我们还将讨论该领域的挑战和研究机会。
