Ionogel Actuators: A Review

ABSTRACT Ionogels are polymer networks infused with ionic liquids. Ionogel actuators are thus devices that convert molecular‐scale responses into flexible, reconfigurable, and stimuli‐responsive macroscopic deformations or motions. Compared with hydrogels, ionogels combine low density, mechanical compliance, and large biomimetic deformation at low operating voltages with sustained ionic conductivity and mechanical and environmental stability, thereby offering significant potential for a wide range of applications. This review systematically examines the development and diversification of ionogel materials, outlining their progression from simple structural supports to advanced functional designs, as well as the synthesis and processing strategies involved. It further discusses the stimuli‐responsive properties and actuation mechanisms of ionogels, together with recent representative cases under various external triggers such as chemical reactions, electromagnetic fields, temperature, humidity, light, and mechanical stress. Finally, the review highlights key actuation applications in artificial limbs, soft robotic grippers, microfluidic systems, lab‐on‐a‐chip devices, sensors, interactive human–machine systems, as well as biomedicine. Despite significant progress, challenges remain in unclear multiscale mechanisms, limited quantitative links between material properties and device‐level performance, limited synergy between materials and functions, unmet requirements for green design and biosafety, and weak system integration with closed‐loop control. Overcoming these issues will broaden the applicability of ionogel actuators, facilitating their reliable integration into diverse soft device platforms and advancing the development of next‐generation smart materials.