Bioinspired Anisotropic Microstructures toward Multimodal Deformations of Low‐Voltage‐Driven Ionic Actuators

Abstract Ionic polymer–metal composites (IPMCs) are a class of ionic actuators considered as potential candidates for future soft electronics that are operable under low voltages (generally <10 V), flexible, lightweight, and can be miniaturized. However, IPMCs can only generate linear bending deformation, but not complex 3D deformation, thus limiting their practical application. Herein, the IPMC actuators with anisotropic stripe microstructures are developed inspired by the botanical systems where microstructural anisotropy of the cell walls can lead to dynamic conformations. The stripe microstructure obtained via one‐way polishing is designed to present a certain angle to the edges of the IPMCs in the longitudinal direction and can be localized. Hence, the IPMCs are subjected to the anisotropic action of the microstructure while bending, yielding a complex 3D deformation. In addition, the large surface area and high ion accessibility area caused by polishing can enhance the actuation performance of IPMCs which is also influenced by the stripe angle, including higher displacement (up to 162%) and larger blocking force (up to 226%). Outstanding electromechanical properties and multimodal deformation model of IPMC actuators with microstructure are demonstrated by applications such as a soft switch, robotic gripper, and imitation of plant organs. This study can open a new vista for making high‐performance actuators and has significant implications for the expansion of the applicability of IPMC actuators.