Rapidly Crosslinked Self‐Healing, Adhesive MXene Hydrogel Toward Electromagnetic/Shockwave Protection and Wide‐Frequency Sensing

ABSTRACT The development of materials integrating electromagnetic interference (EMI) shielding, shockwave protection, and high‐frequency dynamic monitoring is urgently needed for advanced applications such as the Internet of Things. Conventional materials are often limited by single functionality, insufficient mechanical properties, or complex fabrication. Here, we present a rapid, mild solution‐mixing strategy to fabricate multifunctional poly(acrylic acid)/chitosan/MXene hydrogels within seconds at room temperature. Fast gelation is enabled by the synergistic catalytic effect of a tannic acid‐Fe 3+ redox pair and MXene nanosheets. Within the delicately engineered multiscale architecture, highly conductive MXene forms an efficient 3D network, granting the hydrogel EMI shielding over an ultrabroad frequency range of 8.2–40 GHz. Concurrently, the water‐rich porous structure enables shockwave energy absorption and dissipation, alongside wide‐frequency sensing spanning from quasi‐static to ultrahigh‐frequency (shockwave with characteristic frequency components up to 100 MHz) mechanical stimuli. Furthermore, a hybrid network reinforced by covalent crosslinking and dynamic reversible bonds integrates high mechanical strength, robust adhesion, and self‐healing, addressing drawbacks of conventional materials such as brittleness, short service life, and poor interfacial compatibility. This work thus provides a scalable route to multifunctional hydrogels with dual‐wave protection, broad‐range sensing, and high reliability, demonstrating potential for applications in aerospace, flexible electronics, and personal protective equipment.