Thermoresponsive Self‐Healing Carbon Nanotube‐Reinforced Dual‐Network Hydrogels for Wearable Sensors and Information Concealment

The development of multifunctional hydrogels combining mechanical robustness, autonomous self‐healing, electrical conductivity, and stimuli responsiveness remains challenging. Here, we report a thermoresponsive, self‐healing dual‐network hydrogel reinforced with carbon nanotubes (CNTs), integrating reversible dynamic crosslinking, ionic liquid‐mediated phase transitions, and electrical conductivity. The hydrogel combines a borate–poly(vinyl alcohol) (PVA) network with a gelatin/oxidized dextran framework linked through dynamic imine bonds. A phosphonium‐based ionic liquid introduces tunable lower critical solution temperature (LCST)‐type behavior, while CNTs provide mechanical reinforcement and additional conductive pathways. The resulting hydrogels exhibit rapid gelation (<30 s), autonomous self‐healing, stretchability exceeding 1000% strain, and reversible optical switching near 45°C. Their stable, strain‐dependent electrical responses are consistent with contributions from both ionic transport and CNT‐mediated conduction, without compromising thermoresponsivity or dynamic bond exchange. These combined properties enable reliable human motion monitoring, handwriting recognition, Morse code communication, and thermally gated information concealment. This work demonstrates a versatile strategy for integrating dynamic polymer networks with conductive nanomaterials, offering promising opportunities for mechanically resilient wearable electronics, adaptive human–machine interfaces, and thermally programmable information systems.