Multifunctional hydrogel achieves broadband EMI shielding with minimal filler

Mar 05, 2026

A MXene-based double-network hydrogel delivers broadband electromagnetic interference shielding and infrared stealth at just 0.12 wt% filler content.

(Nanowerk News) A newly developed composite hydrogel delivers efficient electromagnetic interference shielding across microwave, terahertz, and infrared frequency bands while using an exceptionally low concentration of conductive filler material. The MXene-based double-network hydrogel, fabricated by a team of researchers led by Zhengwei Wu, addresses a longstanding challenge in flexible electronics: achieving robust EMI shielding performance without sacrificing the mechanical properties that make hydrogels attractive for wearable and soft robotic applications. The study was published in the journal Research (“Multifunctional Hydrogels with Broadband Electromagnetic Interference Shielding and Infrared Stealth Performance in Harsh Environments with Low Conductive Filler Content”).

Key Findings

The proliferation of 5G/6G communications and Internet of Things devices has intensified concerns around electromagnetic interference and radiation pollution. These emissions can degrade device performance, compromise information security, and potentially affect human health. At the same time, aerospace and defense sectors require shielding materials that operate across an ultra-broadband spectrum spanning microwave through terahertz and infrared wavelengths, while also offering high stretchability, mechanical durability, environmental resilience, and reliable strain-sensing capability in demanding operational environments. Conductive hydrogels have emerged as promising candidates for flexible EMI shielding because of their inherent ability to stretch and conform. However, achieving high shielding effectiveness at low filler concentrations has proven difficult. Increasing filler loading improves shielding but typically degrades extensibility and toughness while raising material costs. Most prior research has also focused narrowly on the microwave regime, leaving terahertz and infrared performance largely unexplored. The water-rich polymer matrix of hydrogels further complicates matters, making them susceptible to environmental degradation and reduced shielding under mechanical strain. To overcome these limitations, the research team developed a synergistic treatment strategy combining MXene nanosheets with ammonium sulfate. The approach leverages salt-out processing based on the Hofmeister effect alongside MXene-enabled conductive network formation to produce a double-network composite hydrogel. Even at an extremely low filler content of 0.12 wt%, the resulting MNMSPC hydrogel exhibited roughly three times the overall mechanical performance of untreated counterparts, encompassing improvements in strength, toughness, and stretchability. Mechanistic analysis using a series of control samples revealed that the broadband shielding and infrared stealth properties stem primarily from the continuous conductive network that MXene forms throughout the hydrogel matrix. This network provides high electrical conductivity and drives reflection-based and Ohmic loss mechanisms. The addition of ammonium sulfate introduces mobile ions that enhance ionic polarization and conduction loss. The porous internal structure of the hydrogel also extends the travel path of electromagnetic waves within the material, promoting multiple internal reflections and additional absorption. Critically, the hydrogel retained shielding effectiveness above commercial-grade thresholds and maintained functional infrared stealth under a range of harsh conditions. These included cyclic stretching, prolonged water evaporation, sub-zero freezing, elevated temperatures, direct alcohol lamp flame exposure, and high-strain deformation, demonstrating a level of environmental stability that has been difficult to achieve with hydrogel-based shielding materials. The researchers envision the material as a platform for EMI protection in flexible wearable electronics and soft robotic skins, with particular advantages for stealth applications in complex electromagnetic environments. Future development will target programmable structural designs and external-field-responsive components to enable dynamically tunable and intelligent control of shielding and infrared stealth behavior. The ultimate goal is a high-performance flexible EMI regulation system that integrates sensing, protection, and stealth functions for operation under challenging electromagnetic conditions.