Gallic Acid-Crosslinked EmimBr/AA Ionogels Derived from a Polymerizable Deep Eutectic Solvent toward Intelligent Human–Machine Interfaces

Abstract Flexible ionogels are promising candidates for next-generation human–machine interfaces; however, achieving a balanced combination of mechanical robustness, optical transparency, ionic conductivity, and environmental stability remains a persistent challenge. Herein, we report a multifunctional ionogel derived from a polymerizable deep eutectic solvent (PDES) composed of 1-ethyl-3-methylimidazolium bromide and acrylic acid (EmimBr/AA), in which gallic acid (GA) is introduced as a multivalent hydrogen-bond donor and dynamic physical crosslinking hub, thereby eliminating the need for additional chemical crosslinkers. Benefiting from the synergistic effects of the PDES matrix and GA-mediated molecular-scale interactions, the resulting poly(EmimBr/AA/GA) ionogels exhibit a well-balanced set of properties, including a tensile strength of 0.84 MPa, an elongation at break of 1556%, high optical transparency (>92%), an ionic conductivity of 4.4 × 10–3 S m–1, and strong interfacial adhesion (54 kPa on copper). In addition, the reversible dynamic interactions endow the ionogels with intrinsic self-healing capability (91.2% healing efficiency after 4 h at 100 °C) and recyclability. As proof-of-concept applications, the ionogels were successfully integrated into skin-attachable strain sensors, a 4 × 4 tactile array, and a customized convolutional neural network-assisted smart glove, achieving classification accuracies of 98.5% for 10-class fine hand gestures and 99.08% for 5-class macroscopic body motions. This work offers a general strategy for constructing sustainable, crosslinker-free, high-performance ionogels for intelligent wearable electronics and advanced human–machine interfaces.