Thermally responsive MXene hydrogel for reversibly tunable broadband electromagnetic shielding and temperature sensing

PSM/MXene hydrogels with reversible EMI shielding tunability of 17.95–36.30 dB over 8.2–18 GHz. • Excellent electromagnetic absorption capability and tunable EMI shielding–absorption performance. • Different temperatures detection through resistance changes induced by hydrogel network collapse and water/ion expulsion. Intelligent electromagnetic interference (EMI) shielding materials with reversible tunability hold great promise for flexible electronic and electromagnetic protection devices. In this study, heat-responsive PNIPAM/SA/HPMC/MXene hydrogels were prepared by simple in-situ polymerization and an ion crosslinking method, and their electromagnetic shielding properties can be continuously regulated. The PSM hydrogel exhibits pronounced thermoresponsive behavior near its lower critical solution temperature (LCST) and can undergo a reversible hydration-dehydration transition under external temperature stimuli. A 1.5 mm thick sample achieves a wide-range adjustable shielding performance of 17.95–36.30 dB over 8.2–18 GHz, reversibly switching between electromagnetic shielding and transmission modes. RCS simulation verifies its excellent microwave absorption performance and realizes the integration of temperature-controlled electromagnetic shielding and absorption functions. At the same time, the material has sensitive thermo-responsive resistance and stable strain-sensing characteristics, which can accurately identify ambient temperature and deformation changes. This work provides new ideas for the development of dynamically adjustable EMI shielding materials, highlighting the broad application prospects of composite hydrogels in the fields of intelligent electromagnetic protection and wearable electronics. Download: Download high-res image (204KB) Download: Download full-size image