Alternating Magnetic Field (AMF)-Controlled Magnetothermal Actuation of Hybrid Hydrogel Fiber Mats for Soft Robotics

This study presents a hybrid hydrogel fiber mat system for magnetothermal actuation, designed to address the limitations of conventional temperature-dependent systems in soft robotics. The mats were fabricated via electrospinning, integrating polyurethane (PU) for mechanical flexibility, poly(N-isopropylacrylamide) (PNIPAM) for thermoresponsive behavior, and Fe3O4 nanoparticles for magnetic responsiveness. Alternating magnetic field (AMF)-induced heating of Fe3O4 nanoparticles triggers the lower critical solution temperature (LCST) phase transition of PNIPAM, enabling dynamic, reversible deformation independent of ambient temperature fluctuations. This composite structure allowed diverse deformation modes governed by fiber alignment and cutting angles, facilitating precise and tunable actuation. The demonstrations included flower-like actuation, object gripping with a fiber-based gripper, and maze navigation under magnetic guidance, showing its potential for complex, remote-controlled applications. The incorporation of Fe3O4 nanoparticles enhanced magnetic properties, enabling real-time actuation and reducing reliance on external thermal inputs. This study highlighted a stimuli-responsive material platform with broad potential applications in soft robotics, biomedical devices, and adaptive textiles, providing an innovative solution for remotely controlled and noninvasive actuation systems.