Dynamically Bonded MXene‑Composite Hydrogel via Confined‑Space Gelation for Multimodal Sensing, Photothermal Response and Human‑Machine Interaction.

Achieving synergistic optimization of the hydrogel network through proactive molecular-level design is key to developing flexible electronic materials that combine excellent mechanical, electrical, and multifunctional properties. Regarding this issue, we propose a "thermal activation-annealing synergy" preparation strategy, focusing on revealing the decisive influence of the environment on strengthening intermolecular chain interactions. Compared with an open atmosphere, the confined high-temperature and high-pressure environment greatly promotes effective collisions and hydrogen bond formation between polymer chains (the molecular simulation g(r) value increases nearly tenfold), thereby constructing a denser physical network. Consequently, by integrating the rigid network of κ-carrageenan, the reinforcement from dynamic borate ester bonds, and the conductive/photothermal functions of MXene, the κ-carrageenan-poly(vinyl alcohol)-MXene/borax (KPM-B) composite hydrogel is successfully prepared. This hydrogel exhibits high strength (compressive stress up to 2.4 MPa), high toughness (up to 567.3 kJ/m3), and outstanding fatigue resistance (3000 cycles). Based on these merits, we successfully apply it to full-range monitoring from physiological signals (e.g., ECG) to large-amplitude joint movements, and integrate it into a smart glove to achieve precise human-machine interaction. This work provides a new paradigm for preparing high-performance multifunctional hydrogels through environmental regulation.