Liquid Crystal Elastomer‐Based Magnetic Composite Films for Reconfigurable Shape‐Morphing Soft Miniature Machines

TLDR

Stimuli‑responsive materials, such as soft magnetic composites and liquid crystal elastomers, promise radical advances by enabling precise, fast, wireless actuation and large reversible shape‑morphing in response to environmental stimuli. The study aims to integrate the orthogonal stimuli‑responsiveness of soft magnetic particles and liquid crystal elastomers to create new functionalities for future applications. Magnetic microparticles are embedded within a liquid crystal elastomer film, preserving each material’s independent responsiveness while combining their advantages. The resulting composite yields reconfigurable magnetic soft miniature machines that autonomously adapt their locomotion and function to environmental changes, demonstrated by a robot switching from air to hot liquid, a vine‑like filament that senses and twines around supports, and a light‑switchable magnetic spring, thereby expanding design possibilities for remotely controllable soft robots in complex environments.

Abstract

Stimuli-responsive and active materials promise radical advances for many applications. In particular, soft magnetic materials offer precise, fast, and wireless actuation together with versatile functionality, while liquid crystal elastomers (LCEs) are capable of large reversible and programmable shape-morphing with high work densities in response to various environmental stimuli, e.g., temperature, light, and chemical solutions. Integrating the orthogonal stimuli-responsiveness of these two kinds of active materials could potentially enable new functionalities and future applications. Here, magnetic microparticles (MMPs) are embedded into an LCE film to take the respective advantages of both materials without compromising their independent stimuli-responsiveness. This composite material enables reconfigurable magnetic soft miniature machines that can self-adapt to a changing environment. In particular, a miniature soft robot that can autonomously alter its locomotion mode when it moves from air to hot liquid, a vine-like filament that can sense and twine around a support, and a light-switchable magnetic spring are demonstrated. The integration of LCEs and MMPs into monolithic structures introduces a new dimension in the design of soft machines and thus greatly enhances their use in applications in complex environments, especially for miniature soft robots, which are self-adaptable to environmental changes while being remotely controllable.