Multifunctional ANF/MXene-enhanced hydrogels for flexible EMI shielding and wearable sensing applications

Researchers from Harbin Institute of Technology and their collaborators have developed a multifunctional polyelectrolyte hydrogel reinforced with aramid nanofibers (ANFs) and MXene nanosheets, achieving outstanding performance in absorption-dominated electromagnetic interference (EMI) shielding and wearable sensing. This innovative hydrogel addresses the long-standing challenge of balancing electrical conductivity and effective EMI absorption in flexible electronic materials.

Why the Aramid/MXene Hydrogel Matters

• High EMI Absorption Efficiency: The hydrogel achieves an absorption-to-total shielding effectiveness ratio (SEA/SET) exceeding 94% in the X-band, and a shielding effectiveness of up to 110 dB in the THz range, enabling near-total EMI protection.
• Mechanical Robustness: The hydrogel maintains consistent EMI shielding performance under mechanical deformation, low temperatures, and drying conditions, demonstrating excellent environmental adaptability.
• Wearable Sensing: With high strain sensitivity, fast response (380 ms), and broad strain detection up to 400%, the hydrogel also functions as a flexible sensor for human motion monitoring.

Innovative Design and Mechanisms

• Polyelectrolyte Hydration Engineering: The hydrogel incorporates AMPS and chitosan, enhancing ionic conductivity and forming intermediate water (IW)—a highly mobile water state that facilitates polarization relaxation under electromagnetic fields.
• Multiscale Interface Architecture: ANFs provide structural reinforcement, while MXene nanosheets create conductive pathways and polarization centers. Their interfacial interactions and synergy with IW collectively lead to enhanced absorption-dominated shielding.
• Mechanism-Driven EMI Shielding: Unlike traditional reflection-dominated materials, this hydrogel achieves EMI suppression primarily through conductive loss, interfacial polarization, and dielectric loss from IW, ensuring efficient energy dissipation.

Future Outlook

• Scalability and Integration: The hydrogel can be fabricated via scalable processing and conformally adhered to various substrates, suggesting strong potential for integration into wearable electronics, soft robotics, and on-skin sensors.
• Multifunctionality Expansion: Further studies may explore doping strategies, composite architectures, and neural interface applications to broaden the material’s functionalities in EMI shielding–sensor fusion platforms.
• Mechanistic Insights: This study highlights a new paradigm for absorption-dominated EMI shielding by leveraging hydration dynamics and multicomponent nanostructures, offering a path toward intelligent, adaptive electromagnetic materials.

Stay tuned for more cutting-edge advancements from the Harbin Institute of Technology team as they push the boundaries of EMI shielding and wearable sensing technologies for next-generation soft electronics!