Key Takeaways & Executive Findings
- •• • Achieved average EMI SE of 66.75 dB and SSE/t of 38432.54 dB cm2 g−1 at a film thickness of only 33 μm, demonstrating superior shielding efficiency per unit weight and thickness, critical for weight-sensitive aerospace and portable electronics. • • In-situ grown Ag nanoparticles effectively extend MXene layer spacing, enhancing electromagnetic wave scattering efficiency and contributing to the high shielding performance, as evidenced by the measured SE values. • • The multilayer heterostructure (ANF-PPy/Ag-MXene/ANF-PPy) enables multiple internal reflections and interfacial polarization losses, which are key mechanisms for achieving high EMI SE without compromising flexibility or mechanical integrity. • • The film exhibits high IR reflectivity due to the tight integration of multilayer structures, enabling simultaneous IR thermal camouflage and EMI shielding, a combination rarely achieved in a single material system.
Abstract
The proliferation of electronic devices and wireless communications has escalated the demand for materials that simultaneously provide electromagnetic interference (EMI) shielding and infrared (IR) thermal camouflage, a combination critical for military and civilian applications. Traditional metallic shields suffer from high density, poor processability, and cost, while polymer-based alternatives often lack sufficient shielding effectiveness and environmental stability. Here, we report a multilayer composite film fabricated via layer-by-layer vacuum filtration and hot-pressing, integrating modified aramid nanofibers (ANF) and MXene (Ti3C2Tx) nanosheets. The film architecture comprises ANF-polypyrrole (ANF-PPy) as the matrix and Ag-MXene as the functional filler, with in-situ grown Ag nanoparticles intercalating between MXene layers to enhance interlayer spacing and electromagnetic wave scattering. At a thickness of only 33 μm, the film achieves an average EMI shielding effectiveness (SE) of 66.75 dB and a specific shielding effectiveness (SSE/t) of 38432.54 dB cm2 g−1. The multilayer structure promotes multiple internal reflections and interfacial polarization losses, while the tight integration ensures high IR reflectivity. This work establishes a foundation for developing multifunctional protective materials with dual EMI shielding and IR camouflage capabilities, addressing the critical bottleneck of simultaneous performance in ultrathin, flexible formats.
1. Introduction
The rapid advancement of electronic devices and wireless communication systems has intensified the dual threats of electromagnetic interference (EMI) and infrared (IR) signature exposure, particularly in aerospace, defense, and high-reliability electronics. Traditional shielding materials, such as metals, offer excellent EMI shielding and low IR emissivity but are plagued by high density, poor processability, and elevated costs, limiting their deployment in weight-sensitive and flexible applications. Polymer-based composites have emerged as alternatives, yet they often struggle to achieve sufficient shielding effectiveness (SE) and environmental stability, especially under demanding operational conditions. The core challenge lies in designing materials that can simultaneously attenuate electromagnetic waves and suppress IR emissions without sacrificing mechanical flexibility or processability.
MXenes, particularly Ti3C2Tx, have garnered attention for their high electrical conductivity, solution processability, and low IR emissivity, making them promising candidates for EMI shielding and IR camouflage. However, MXene-based materials face critical bottlenecks: susceptibility to oxidation, poor mechanical strength, and the need for structural engineering to maximize electromagnetic wave attenuation. This study addresses these limitations by constructing a multilayer heterostructure comprising aramid nanofibers (ANF) and polypyrrole (PPy) as a robust matrix, with Ag-decorated MXene as the functional filler. The layer-by-layer assembly and hot-pressing process create strong interfacial bonding and compositional synergy, while in-situ grown Ag nanoparticles expand the MXene interlayer spacing, enhancing scattering and absorption losses. This design achieves exceptional EMI SE and IR reflectivity in an ultrathin film, offering a viable pathway for multifunctional protective materials.
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Yu Fan, Jiangyu Fang, Ruoqi Wang, Xiaoyun Liu, Qixin Zhuang, Peiyuan Zuo (2026). Enhancing interfacial bonding and compositional synergy in ANF-PPy/Ag-MXene/ANF-PPy multilayer heterostructures for efficient electromagnetic interference shielding and infrared thermal camouflage. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-3664-x
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Frequently Asked Questions
What is the maximum EMI shielding effectiveness achieved and at what thickness?
The film achieves an average EMI SE of 66.75 dB at a thickness of only 33 μm, with a specific shielding effectiveness (SSE/t) of 38432.54 dB cm2 g−1, indicating exceptional performance per unit weight and thickness.
How does the incorporation of Ag nanoparticles enhance the shielding performance?
In-situ grown Ag nanoparticles intercalate between MXene layers, effectively extending the interlayer spacing. This increases the surface area for electromagnetic wave scattering and creates additional interfaces for polarization losses, thereby enhancing the overall shielding effectiveness.
What are the key mechanisms contributing to EMI shielding in this multilayer structure?
The multilayer heterostructure (ANF-PPy/Ag-MXene/ANF-PPy) promotes multiple internal reflections at the interfaces, leading to enhanced absorption and multiple scattering of electromagnetic waves. Additionally, the conductive network formed by MXene and Ag nanoparticles facilitates ohmic losses, while interfacial polarization between different layers contributes to dielectric losses.
How does the film achieve infrared thermal camouflage in addition to EMI shielding?
The tight integration of the multilayer structure results in high infrared reflectivity, which minimizes thermal emission and aids in thermal camouflage. The combination of low IR emissivity from MXene and the dense, layered architecture contributes to this dual functionality.
What are the potential scalability and environmental stability of this material?
The fabrication process involves layer-by-layer vacuum filtration and hot-pressing, which are scalable techniques. The use of aramid nanofibers provides mechanical robustness and environmental stability, addressing the oxidation susceptibility of MXene. However, further studies are needed to assess long-term durability under real-world conditions.
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