3D-Printed Multifunctional Hydrogel for Integrated Electromagnetic Interference Shielding, Infrared Stealth, and Wearable Sensing

The growing demand for wearable electronics and infrared stealth technologies has highlighted the limitations of traditional electromagnetic interference (EMI) shielding materials, which often lack flexibility, lightweight design, and multifunctional integration. Although hydrogels present a promising platform due to their flexibility, adhesion, and sensing capabilities, the integration of multiple functions into a single material system through a straightforward fabrication process remains challenging. In this study, we developed a one-pot synthesized multifunctional ANE hydrogel that incorporates an ionic liquid (EBIB) as a conductive medium. Unlike conventional conductive fillers, such as silver nanowires or MXene, EBIB enhances both conductivity and interfacial polarization, achieving an EMI shielding efficiency of 34.5 dB in the X-band, surpassing many reported polymer-based shields. By combining this with vat photopolymerization 3D printing, we fabricated tailored topological structures that promote electromagnetic wave dissipation and suppress infrared thermal transmission. The hydrogel demonstrates effective infrared stealth, maintaining a low temperature increase of 24 °C on a 100 °C hot stage for 20 min, outperforming typical nonporous hydrogel coatings. Furthermore, the material exhibits strong adhesion, high strain sensitivity (gauge factor = 5.282 over 150-300% strain), fast response (165 ms), and cycling stability, exceeding the performance of many existing ionic hydrogels in motion sensing. By integration of EMI shielding, infrared camouflage, and wearable sensing in a single 3D-printable system, this study offers a competitive material solution for next-generation multifunctional sensors.