Ionic Double‐Network Hydrogels for Integrated Electromagnetic Shielding and Self‐Powered Sensing in Wearable Electronics

Abstract Cardiovascular implantable electronic devices (CIEDs) face dual challenges of high‐frequency electromagnetic interference and functional integration. This work reports a multifunctional material constructed via a double‐network ionic hydrogel strategy, enabling the integrated realization of efficient electromagnetic shielding and self‐powered physiological monitoring. An interpenetrating network skeleton is formed through physical crosslinking of sodium alginate (SA) with Ca 2 ⁺ and in situ polymerization of acrylamide (AM). By regulating the specific coordination of ions to induce directional channels and synergistically regulating salt concentration with hydration, an absorption‐dominated shielding mechanism centered on ion polarization‐interface relaxation is established. The optimized h ‐CA‐PAM‐Li⁺‐1.0 hydrogel exhibits an electromagnetic interference (EMI) shielding effectiveness (SE T ) of 63.75 dB in the X‐band, with absorption loss accounting for over 93%. Leveraging the excellent ionic conductivity of the hydrogel, a self‐powered sensor encapsulated in PDMS films and integrated with wireless modules is fabricated, capable of real‐time capture of physiological signals such as heartbeat while maintaining high sensitivity and anti‐interference capability in dynamic environments. Free of traditional conductive fillers, this material combines biocompatibility, low cost, and designability, providing a material‐device‐system integrated solution for electromagnetic protection and intelligent monitoring of implantable electronic devices and opening a new research paradigm for multifunctional shielding materials.