MXene Nanosheet-Reinforced Polyacrylamide/Poly(vinyl alcohol) Interpenetrating Network Hydrogel for Electromagnetic Shielding and Motion Monitoring

With the advancement of flexible electronics and wearable devices, the development of integrated sensing materials that simultaneously possess high stretchability, sensitivity, and efficient electromagnetic interference shielding has become a prominent research focus. In this study, we designed and synthesized a multifunctional interpenetrating network hydrogel composed of poly(vinyl alcohol), acrylamide, sodium alginate, choline chloride, and MXene. Through a hybrid physicochemical cross-linking strategy, the hydrogel achieves an elongation at break of 1461% and a tensile strength of 101.89 kPa. It exhibits a broad sensing range of up to 600% strain with a high gauge factor of 5.8, enabling stable monitoring of both subtle physiological signals and large-scale joint motions. Furthermore, by leveraging the continuous conductive network formed by MXene nanosheets, the hydrogel demonstrates a significant EMI shielding effectiveness of 33 dB in the X-band (8.2–12.4 GHz), primarily governed by the synergistic effects of reflection and absorption. The hydrogel also displays excellent biocompatibility, adhesiveness, and cycling stability, retaining approximately 84.67% of its initial stress after 100 loading–unloading cycles at 600% strain. This work provides valuable insights into the design of multifunctional integrated flexible sensors and shows considerable promise for applications in health monitoring, human–machine interaction, and electromagnetic protection.