Self-healing and hyperelastic magneto-iono-elastomers through molecular confinement of magnetic anions

Magneto-responsiveness in living organisms, exemplified by migratory birds navigating vast distances, offers inspiration for soft robots and human-computer interfaces. However, achieving both high magneto-responsiveness and resilient mechanical properties in synthetic materials has been challenging. Here, we develop magneto-iono-elastomers (MINEs), combining exceptional magnetization [2.6 emu (electromagnetic units)/g] with hyperelasticity and self-healability. Such a MINE consists of a magnetic ionic liquid (MIL; [Emim][FeCl₄]) and a urethane group-based polymer that can distinctively confine magnetic anions through strong intermolecular interactions, including potential hydrogen bonds and metal-coordination bonds. This confinement enables high MIL loading (80 wt %) while maintaining structure integrity, resulting in a high ionic conductivity exceeding 10^-3 S/cm. Furthermore, the synergistic interplay of these reversible bonds in MINEs contributes to an outstanding elastic recovery that surpasses 99%, alongside good self-healing capabilities. The unique combination of these attributes positions MINE as a promising candidate for diverse magnetoelectronic applications, encompassing wearable strain sensors, contactless magneto-responsive electronics, see-through touch panels, and soft magnetic carriers.