One‐Step Manufacturing of Supramolecular Liquid‐Crystal Elastomers by Stress‐Induced Alignment and Hydrogen Bond Exchange

Abstract

AbstractLiquid‐crystal elastomers (LCEs) capable of performing large and reversible deformation in response to an external stimulus are an important class of soft actuators. However, their manufacturing process typically involves a multistep approach that requires harsh conditions. For the very first time, LCEs with customized geometries that can be manufactured by a rapid one‐step approach at room temperature are developed. The LCEs are hydrogen bond (H‐bond) crosslinked main chain polymers comprising flexible short side chains. Applying a stretching/shear force to the LCE can simultaneously induce mesogen alignment and H‐bond exchange, allowing for the formation of well‐aligned LCE networks stabilized by H‐bonds. Based on this working principle, soft actuators in fibers and 2D/3D objects can be manufactured by mechanical stretching or melt extrusion within a short time (e.g. <1 min). These actuators can perform reversible macroscopic motions with large, controlled deformations up to 38 %. The dynamic nature of H‐bonds also provides the actuators with reprocessability and reprogrammability. Thus, this work opens the way for the one‐step and custom manufacturing of soft actuators.