Search

Molybdenum carbide (MoC) integrated into a carbon matrix, known for its robust interfacial polarization, emerges as a promising ultra‐lightweight EM wave absorber. However, the fabrication of such materials remains a formidable challenge. Herein, a facile and scalable strategy for preparing MoC‐incorporated carbon matrix employing ZnMo‐HZIF foam material through ball‐milling foaming and calcination process as a promising electromagnetic wave materials (EWAMs). In detail, the 3D foam structure reaches impedance matching, and heterogeneous interfaces of N‐doped MoC‐incorporated carbon material (MoC/NC) promote the dipolar/interfacial polarization, confirmed by the hologram. Mo defects induced the charge transfers, displaying an enhanced interfacial polarization. At 15 wt.%, the minimum reflection loss of the obtained sample at 2.5 mm reaches −47.56 dB, and the effective absorption bandwidth spans 4.40 GHz, nearly covering the full X band. Additionally, the assembly device testing demonstrates their excellent self‐cleaning, heat‐insulation, flame retardancy, and infrared stealth properties. This work presents a new perspective on the synergistic effect of structure and components on electromagnetic wave absorption performance and provides a new approach for preparing lightweight and high‐performance MOF‐based electromagnetic wave absorbing materials. [ABSTRACT FROM AUTHOR]

There is an urgent need for multifunctional materials that possess high absorption and infrared stealth capabilities to address the increasingly complex and severe electromagnetic pollution. This research explores how the microstructure of components and the design of the absorber impact the stealth performance of electromagnetic and infrared waves. This research involved designing and fabricating a bi-layer sample with a hierarchical structure consisting of FeCoNi magnetic particles as the absorbing layer and Cu 2 O micro-cube/ h -BN nanocomposite as the matching layer. The particular design of the absorber was instrumental in intensifying the synergistic relationship between dielectric and magnetic loss, thereby achieving a superior level of impedance matching and absorption efficacy. The optimized microwave absorption performance was achieved by tuning thickness and arrangement of each layer. It shows that the minimum reflection loss for bilayer sample reaches −38 dB with a total thickness of only 1.2 mm, and effective absorption bandwidth of 4.4 GHz which covers 75 % of the entire ku frequency band. Its excellent electromagnetic and infrared wave stealth performance may be attributed to enhanced heterogeneous interfaces and consequently polarization relaxation along with magnetic loss, which result from multi-component synergy and the unique 3D hierarchical microstructure and interconnection between particles. [ABSTRACT FROM AUTHOR]

Highlights Lightweight dual-functional segregated nanocomposite foams are developed via the supercritical CO2 (SC-CO2) foaming combined with hydrogen bonding assembly and compression molding strategy The segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity. Excellent absorption-dominant electromagnetic interference shielding performances are achieved owing to the synchronous construction of microcellular structures and segregated structures

In order to explore the influence of the infrared stealth technology on the performance of the integrated helicopter/engine system, an integrated modeling method of helicopter/engine/infrared suppressor is proposed. Firstly, based on the power calculation model of the helicopter, combined with the high-precision turboshaft engine component-level model, an integrated simulation platform is built, which takes into account the nonlinear characteristics. Then, the aerodynamic characteristics of infrared suppressors under different engine operation states are studied by CFD numerical computation method, and the infrared radiation characteristics are obtained through combining the positive and negative ray tracing method and narrow band model method. Ultimately, the utilization of the power turbine outlet stagnation pressure is employed as the pivotal interface linking the turboshaft engine and the infrared suppressor in order to formulate an integrated model encompassing the helicopter, engine, and infrared suppressor subsystems. The simulation results demonstrate that compared with the conventional exhaust system, the application of the infrared suppressor greatly enhances the stealth performance of the helicopter, but also results in the unexpected decrease in engine output power. Moreover, the specific fuel consumption of the turboshaft engine increase and the compressor surge margin decreases in case of the consistent flight condition. [ABSTRACT FROM AUTHOR]

In modern war of “find and destroy,” hiding the target is one of the essential means to improve battlefield survivability of personnel, weapons, and equipment. Infrared stealth technology started to emerge when hiding in the visible light band could no longer meet the protection requirements. With the rapid development of infrared detection technology, infrared stealth materials are gradually diversified. At present, infrared stealth technology no longer focuses only on low infrared emissivity, but from multiple perspectives to achieve target stealth, such as the tunability of optical properties, good thermal management, and multi‐spectral compatibility stealth. At the same time, the infrared stealth of the target is gradually shifted from passive to active, emphasizing dynamic integration of the target and the environment. This review summarizes research progress, development, and application of infrared stealth materials. Camouflage dye and infrared stealth coating are classified as traditional technologies, however new developments and novel processes from literature can be constantly retrieved over the years. In addition to dyeing/coating technologies, this review also highlights advanced infrared stealth materials such as thermal insulation materials, phase change materials, electrochromic materials, metamaterials, and bionic materials. Outlines of the advanced technologies are mainly focused on those published in recent years. Challenges and prospects for the future development of infrared stealth materials are presented at the end of the review. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-interfacial bridging engineering was used to prepare the flexible MXene film. • Highly efficient electromagnetic shielding capability is achieved through a dense multiple conductive network. • The total EMI shielding effectiveness can be increased by 27 % with the highest value of 67.9 dB. • The infrared emissivity is as low as 0.173 within the 8–14 μm. • The mechanism of the shielding and photothermal compatibility along with the durability are proposed. Accompanied by the progressive development of electronic equipment, excellent electromagnetic interference (EMI) shielding materials display a satisfying prospect in protecting electronic devices against electromagnetic pollution/radiation, while integrating energy conversion. Heretofore, it remains a conundrum to availably construct thin films with multi-interfacial bridging engineering as multifunctional shielding devices. To effectively achieve electromagnetic wave attenuation and integrate energy conversion, a co-mixed vacuum-assisted filtration strategy is designed to synthesize Au@MXene/cellulose nanocrystal/dodecylbenzenesulfonic acid-doped polyaniline (AMCP) films. Profited from the interfacial engineering, the total EMI shielding effectiveness (SE) can be increased by 27 % with the highest value of 67.9 dB. MXene with localized surface plasmon resonance characteristics gives the composite films good energy conversion performance, that is, the composite film can be rapidly heated up to 100 °C under the irradiation of an infrared lamp, and its surface temperature remains stable after continuous irradiation. Additionally, the infrared emissivity is as low as 0.173 within the 8–14 μm, which is necessary to adapt various application scenarios. Therefore, it is reliable that the AMCP films constructed by multicomponent offer a facile strategy for MXene-based EMI shielding devices with integration characteristics. [ABSTRACT FROM AUTHOR]

Researching and manufacturing materials that possess both electromagnetic interference (EMI) shielding and infrared stealth capabilities is of great significance. Herein, an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe3O4/Ag nanoparticles on the surface of polyimide (PI) fiber (PFA), and followed by bonding with a commercial Cu/Ni mesh. The synergistic assembly of PFA and Cu/Ni promotes the rational construction of hierarchical impedance matching, inducing electromagnetic waves (EMW) to enter the composite and be dissipated as much as possible. Meanwhile, the existence of Cu/Ni mesh on back of PFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite, leading to a lower-reflectivity (0.26) EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness (430 µm). More importantly, the fluffy PFA nonwoven fabric and metal Cu/Ni mesh endow composite with good thermal insulation and low infrared emissivity, resulting in excellent infrared stealth performance in various environments. As a result, such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation. [ABSTRACT FROM AUTHOR]

With the accelerated development of modern detection and communication technology, the multifunctional wearable materials with excellent electromagnetic interference (EMI) shielding, infrared stealth, and human monitoring for improving military combat capability have received extensive attention. In this work, the lightweight melamine foam (MF)@silver nanowires (AgNWs)-iron nanowires (FeNWs) (AgFe-MF) was fabricated by a vacuum-assisted dip-coating method. Due to the porous structure and synergistic electrical and magnetic losses, this lightweight (0.115 g/cm3) composite foam with an ultra-low filler content (0.62 vol.%) exhibited an ideal EMI shielding efficiency of 38.4 dB. On the other hand, the AgFe-MF realized a powerful multifunctional integration. The surface saturation temperature of the AgFe-MF reached 94.2 °C under a low applied voltage of 1.8 V and remained extremely fast heating and cooling response and terrific working stability, resulting in excellent infrared stealth and camouflage effects. Furthermore, taking virtues of the elastic porous conductive architecture, the AgFe-MF was utilized as a piezoresistive sensor exhibiting board compressive interval of 0–1.62 kPa (50% strain) with a good sensitivity of 0.57 kPa−1. This work will provide new ideas and insights for developing multifunctional wearable devices in the fields of EMI shielding, thermal management, and piezoresistive sensing. [ABSTRACT FROM AUTHOR]

With the development of detection and identification technology, infrared stealth is of great value to realize anti-reconnaissance detection of military targets. At present, infrared stealth materials generally have deficiency, such as complex structure, inconvenient radiation regulation and cumbersome preparation steps, which greatly limit the practical application of infrared stealth materials. In view of the above deficiency of infrared stealth materials, we proposed a kind of multilayer film for infrared stealth using VO2 thermochromism based on the temperature response mechanism of tuna to adjust its color, and through the intelligent reversible radiation regulation mechanism to meet the infrared stealth requirements of tanks in different actual scenes. The results show that when the temperature increases from 300 K to 373 K, the peak emissivity of the film decreases from 94% to 20% in the 8–14 µm band after structural optimization, which can realize the infrared stealth of the high temperature target in the 8–14 µm band. The average emissivity of the multilayer film for infrared stealth at 3–5 µm and 8–14 µm band can be reduced to 34% and 27% at 373 K, and the peak emissivity at 5–8 µm band can reach 65%, realizing dual-band infrared stealth in the 3–5 µm and 8–14 µm bands and heat dissipation in the 5–8 µm band. The multilayer film for infrared stealth based on VO2 thermochromism designed by the authors can meet the characteristics of simple film structure, convenient radiation regulation and simple preparation. [ABSTRACT FROM AUTHOR]

The development of electronic skin with dual stealth functionality is crucial for enabling devices to operate effectively in dynamic electromagnetic environments, thereby facilitating intelligent electromagnetic protection for autonomous perception. However, achieving compatibility between terahertz (THz) and infrared (IR) stealth technologies remains largely unexplored due to their inherent contradictions. Herein, inspired by natural corals, a novel coral‐like multi‐scale composite foam (CMSF) was proposed that ingeniously reconciles these contradictions. The design capitalizes on the conductive network and heat insulation properties of the foam skeleton, the loss effects and low infrared emission of metal particles, and the infrared transparency of magneto‐optical materials. This approach leads to the realization of a THz‐IR bi‐stealth electronic skin concept. The CMSF exhibits a maximum reflection loss of 84.8 dB in the terahertz band, while its infrared stealth capability ensures environmental adaptability under varying temperatures. Furthermore, the electronic skin exhibits exceptional sensitivity and reliability as a wearable device for perceiving environmental changes. This advanced material, combining multispectral stealth with sensing capabilities, holds immense potential for applications ranging from camouflage technology to smart wearables. [ABSTRACT FROM AUTHOR]

Highlights: Lightweight dual-functional segregated nanocomposite foams are developed via the supercritical CO2 (SC-CO2) foaming combined with hydrogen bonding assembly and compression molding strategy The segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity. Excellent absorption-dominant electromagnetic interference shielding performances are achieved owing to the synchronous construction of microcellular structures and segregated structures Lightweight infrared stealth and absorption-dominant electromagnetic interference (EMI) shielding materials are highly desirable in areas of aerospace, weapons, military and wearable electronics. Herein, lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO2 (SC-CO2) foaming combined with hydrogen bonding assembly and compression molding strategy. The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity, and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures. Particularly, the segregated nanocomposite foams present a large radiation temperature reduction of 70.2 °C at the object temperature of 100 °C, and a significantly improved EM wave absorptivity/reflectivity (A/R) ratio of 2.15 at an ultralow Ti3C2Tx content of 1.7 vol%. Moreover, the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles. The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace, weapons, military and wearable electronics. [ABSTRACT FROM AUTHOR]

Intelligent and diversified development of modern detection technology greatly affects the battlefield survivability of military targets, especially infrared, acoustic wave, and radar detection expose targets by capturing their unavoidable infrared radiation, acoustic wave, and electromagnetic wave information, greatly affecting their battlefield survival and penetration capabilities. Therefore, there is an urgent need to develop stealth-protective materials that can suppress infrared radiation, reduce acoustic characteristics, and weaken electromagnetic signals. Fibrous three-dimensional porous materials, with their high porosity, excellent structural adjustability, and superior mechanical properties, possess strong potential for development in the field of stealth protection. This article introduced and reviewed the characteristics and development process of fibrous three-dimensional porous materials at both the micrometer and nanometer scales. Then, the process and characteristics of preparing fibrous three-dimensional porous materials through vacuum forming, gel solidification, freeze-casting, and impregnation stacking methods were analyzed and discussed. Meanwhile, their current application status in infrared, acoustic wave, and radar stealth fields was summarized and their existing problems and development trends in these areas from the perspectives of preparation processes and applicability were analyzed. Finally, several prospects for the current challenges faced by fibrous three-dimensional porous materials were proposed as follows: functionally modifying fibers to enhance their applicability through self-cross-linking; establishing theoretical models for the transmission of thermal energy, acoustic waves, and electromagnetic waves within fibrous porous materials; constructing fibrous porous materials resistant to impact, shear, and fracture to meet the needs of practical applications; developing multifunctional stealth fibrous porous materials to confer full-spectrum broadband stealth capability; and exploring the relationship between material size and mechanical properties as a basis for preparing large-scale samples that meet the application's requirement. This review is very timely and aims to focus researchers' attention on the importance and research progress of fibrous porous materials in the field of stealth protection, so as to solve the problems and challenges of fibrous porous materials in the field of stealth protection and to promote the further innovation of fibrous porous materials in terms of structure and function. [ABSTRACT FROM AUTHOR]

Controlling the orientation of two-dimensional MXene within layered films is essential to optimize or tune their mechanical properties and electromagnetic interference shielding (EMI) performance, but achieving the high orientation MXene layers on an industrial scale remains a challenging goal. In this paper, a scalable layer-by-layer blade coating (LbLBC) method was employed to fabricate highly oriented MXene/polyvinyl alcohol (PVA) films. During the LbLBC process, MXene/PVA colloid suffered a strong shearing effect, which induced the ordered alignment of MXene nanosheets along the direction of the blade movement. The orientation of MXene can be effectively adjusted by changing the scraping gap of LbLBC, achieving a maximum Herman orientation factor f of 0.81. As a result, the mechanical properties and EMI performance of the as-prepared MXene/PVA films are in direct proportion to their orientation, with the optimal values of tensile strength of 145.5 MPa, fracture strain of 19.6%, toughness of 17.7 MJ·m−3, and EMI shielding effectiveness of 36.7 dB. Furthermore, the inherently low mid-infrared (mid-IR) emissivity of MXene, combined with the densely oriented structure affords the composite films with IR stealth, resulting in a substantial decrease from 150 to 66.1 °C in the radiative temperature of a surface. Conclusively, these scalable MXene/PVA films exhibit remarkable potential for integration into the next generation of multifunctional protective camouflage materials. [ABSTRACT FROM AUTHOR]

Spectral selective emission materials, characterized by their high emission efficiency within specific wavelength ranges, play a crucial role in various fields such as infrared stealth and radiative cooling. In this study, leveraging the tunneling effect of ultrathin metal layers and the impedance matching principle, we designed a one-dimensional multilayer thin film structure composed of Mo/Ge/Al. This design successfully achieved spectral selective emission within the 3–14 μm infrared spectrum range, showcasing superior high-temperature infrared stealth capabilities. Research findings indicate that the infrared atmospheric window (ε3–5 μm = 0.40, ε8–14 μm = 0.30) maintains a low emissivity within the temperature range from room temperature to 400 °C, while high emissivity in non-infrared atmospheric windows (ε5–8 μm = 0.81) enables radiative cooling. The use of high emissivity in the non-infrared atmospheric window reduced the surface temperature of this structure by 15.3 °C compared to untreated Si substrate under similar heating conditions. The temperature reduction was 34.1 °C when compared to a Si substrate coated with a 200 nm Al film. This straightforward and easily scalable structure not only presents novel solutions for applications in infrared stealth and radiative cooling but also holds vast potential for diverse fields including military, aerospace, and industrial manufacturing, injecting fresh impetus and possibilities into technological advancement.

MXene‐based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti‐oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long‐term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene‐based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water‐soluble polymers; while the HSi molecules can act as efficient cross‐linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long‐term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long‐term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene‐coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance. [ABSTRACT FROM AUTHOR]

With the development of detection methods, the intelligent and high-precision military stealth detection technology has put forward higher requirements for the performance of stealth materials, the traditional materials are limited by their own performance, and it is difficult to achieve stealth requirements such as lightweight, broadband, and strong absorption. However, the metamaterials have great potential for development in the field of stealth due to their ability to design, adjust structures, and achieve related performance according to human will. Therefore, the research on metamaterials in the field of military stealth has received great attention.The development, special properties and applications of metamaterials were reviewed in this paper, focusing on the research and development of radar stealth metamaterials, infrared stealth metamaterials, radar/infrared compatible stealth metamaterials, and laser/infrared compatible stealth metamaterials. Finally, it was pointed out that the research of metamaterials in the field of military stealth mostly stays in the experimental stage, and it is difficult to adapt to the complex and changeable practical environment for practical application, the research of metamaterials should be focused on low-cost preparation and application, broadband multi-band compatibility, as well as high temperature resistance, high corrosion resistance and high outdoor stability.

Ti3C2Tx materials have been developed to have application space in many fields, but there are not many works that can be compatible with infrared (IR) stealth and electromagnetic interference (EMI) shielding at the same time. To realize the multiband high EMI shielding of Ti3C2Tx materials, and to achieve stealth effect in the IR band, in this work, a composite textile is prepared by combining the Ti3C2Tx material with a carbon cloth and sputtering a very thin gold film on the surface. This composite textile can realize high EMI shielding compatible with IR stealth, in which the EMI shielding efficiency for microwave Xa‐band (8GHza‐12.4GHz) is up to 71.8 dB, for microwave Kaa‐band (26.5GHza‐40GHz) is up to 75.02 dB, and for terahertza‐band is about 30 dB. IR emissivity is as low as 0.1, and the lowest emissivity under a certain temperature reaches 0.07, which can withstand a high temperature of 500 °C. In addition, this composite textile has flexible and bendable wear. The thickness of the whole textile is about 400 µm, of which the Ti3C2Tx material thickness is only about 10 µm, the thinnest reaches 2 µm. Such a textile can be used in both people's livelihood and military applications, which has far‐reaching significance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The rapid development of infrared surveillance technologies has attracted great attention for scientists to design advanced functional materials with prominent infrared stealth and thermal camouflage effectiveness. In the current study, a sandwich‐like functional composite based on a crosslinked polyimide aerogel, a meso‐erythritol (mE)‐based phase‐change composite, and an MXene film has been developed to achieve long‐term thermal camouflage at elevated temperatures. In this composite system, the lower aerogel layer can act as a barrier to insulate heat transfer through its layer‐stacking structure under ultralow directional thermal conduction. The introduction of the middle phase‐change composite layer ensures that the composite system obtains a dynamical temperature‐regulation capability through sensible and latent heat absorption of mE as a phase change material, while the upper MXene layer provides a very low emissivity surface for the system. As a result, the developed composite achieves a significant reduction in the thermal radiation temperature of a high‐temperature target. Moreover, the MXene film exhibits good electromagnetic interference shielding effectiveness, making the sandwich‐like composite obtain a thermal camouflage capability in various complicated scenarios. This work provides a promising approach for the design of advanced functional materials to realize long‐term infrared stealth and thermal camouflage of high‐temperature targets in security protection and counter‐surveillance. [ABSTRACT FROM AUTHOR]

Microwave and infrared–thermal radiation-compatible shielding fabrics represent an important direction in the development of wearable protective fabrics. Nevertheless, effectively and conveniently integrating compatible shielding functions into fabrics while maintaining breathability and moisture permeability remains a significant challenge. Here, we take hydrophilic PVA-co-PE nanofibrous film-coated PET fabric (NFs/PET) as a flexible substrate and deposit a dielectric/conductive (SiO2/Al) bilayer film via magnetron sputtering. This strategy endows the fabric surface with high electrical conductivity, nanoscale roughness comparable to visible and infrared waves, and a dielectric–metal contact interface possessing localized plasmon resonance and Mie scattering effects. The results demonstrate that the optimized SiO2/Al/NFs/PET composite conductive fabric (referred to as S4-1) possesses favorable X-band electromagnetic interference (EMI) shielding effectiveness (50 dB) as well as excellent long-wave infrared (LWIR) shielding or IR stealth performance (IR emissivity of 0.60). Notably, the S4-1 fabric has a cooling effect of about 12.4 °C for a heat source (80 °C) and an insulating effect of about 17.2 °C for a cold source (−20 °C), showing excellent shielding capability for heat conduction and heat radiations. Moreover, the moisture permeability of the S4-1 fabric is about 300 g/(m2·h), which is better than the requirement concerning moisture permeability for wearable fabrics (≥2500–5000 g/(m2·24 h)), indicating excellent heat and moisture comfort. In short, our fabrics have lightweight, thin, moisture-permeable and excellent shielding performance, which provides novel ideas for the development of wearable multi-band shielding fabrics applied to complex electromagnetic environments. [ABSTRACT FROM AUTHOR]

Abstract MXene‐based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti‐oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long‐term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene‐based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water‐soluble polymers; while the HSi molecules can act as efficient cross‐linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long‐term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long‐term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene‐coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance.

Intelligent and diversified development of modern detection technology greatly affects the battlefield survivability of military targets, especially infrared, acoustic wave, and radar detection expose targets by capturing their unavoidable infrared radiation, acoustic wave, and electromagnetic wave information, greatly affecting their battlefield survival and penetration capabilities. Therefore, there is an urgent need to develop stealth-protective materials that can suppress infrared radiation, reduce acoustic characteristics, and weaken electromagnetic signals. Fibrous three-dimensional porous materials, with their high porosity, excellent structural adjustability, and superior mechanical properties, possess strong potential for development in the field of stealth protection. This article introduced and reviewed the characteristics and development process of fibrous three-dimensional porous materials at both the micrometer and nanometer scales. Then, the process and characteristics of preparing fibrous three-dimensional porous materials through vacuum forming, gel solidification, freeze-casting, and impregnation stacking methods were analyzed and discussed. Meanwhile, their current application status in infrared, acoustic wave, and radar stealth fields was summarized and their existing problems and development trends in these areas from the perspectives of preparation processes and applicability were analyzed. Finally, several prospects for the current challenges faced by fibrous three-dimensional porous materials were proposed as follows: functionally modifying fibers to enhance their applicability through self-cross-linking; establishing theoretical models for the transmission of thermal energy, acoustic waves, and electromagnetic waves within fibrous porous materials; constructing fibrous porous materials resistant to impact, shear, and fracture to meet the needs of practical applications; developing multifunctional stealth fibrous porous materials to confer full-spectrum broadband stealth capability; and exploring the relationship between material size and mechanical properties as a basis for preparing large-scale samples that meet the application’s requirement. This review is very timely and aims to focus researchers’ attention on the importance and research progress of fibrous porous materials in the field of stealth protection, so as to solve the problems and challenges of fibrous porous materials in the field of stealth protection and to promote the further innovation of fibrous porous materials in terms of structure and function.

Ti3C2Tx MXene is expected to achieve infrared stealth by regulating its thermal radiation properties. In this study, Ti3C2Tx MXene films were prepared by using the acid etching method, and the effects of etchants (HCl/LiF, HF, and NH4HF2) on the film structure as well as the infrared radiation properties were systematically studied. The intercalation process used to exfoliate single/few-layer nanosheets was found to accelerate the oxidation and increase the resistance of MXene. The mechanism behind these effects on emissivity was explained in detail. Based on these findings, the most suitable preparation process for low-emissivity MXene was selected. The resulting Ti3C2Tx film (HL-f), which used HCl/LiF as an etchant for Ti3AlC2, has a high conductivity of 3119 S/cm that reflects numerous infrared waves reaching its surface while exhibiting a low emissivity of only 0.13. The colloidal solution (HL-s) made with HCl/LiF as an etchant was sprayed directly onto a PI substrate as a coating with infrared stealth capabilities, thermal stability, and Joule heating properties, reducing the emissivity from 0.87 to 0.14. This work provides guidance for improving MXene preparation methods and their applications in related fields while demonstrating the great potential of HCl/LiF-etched Ti3C2Tx MXene as a low-emissivity infrared stealth material. [ABSTRACT FROM AUTHOR]

AZO/Cu/AZO/CTO films were prepared on PET substrates by magnetron sputtering. The effects of CTO (CeO-TlO 2) layer thickness on the microstructure, optical properties, infrared emissivity and conductivity of AZO/Cu/AZO/CTO elms were systematically studied. With the increase of CTO layer thickness, the band gap becomes narrower, the UV blocking rate and near infrared blocking rate is improved, and the visible eight transmittance s reduced. At the same time, the CTO layer s beneficial to reduce the surface resistance and infrared emissivity of the multilayer film. When the thickness of CTO layer is 34.2 nm, the UV blocking rate is 92.0 %, the infrared blocking rate is 46.5 %, the visible light transmittance is 62.5 %, and the infrared emissivity in 814 JM is 0.163. Therefore, the AZO/Cu/AZO/CTO film has spectral selectivity and low infrared which is a potential soar barrier and infrared stealth material [ABSTRACT FROM AUTHOR]

In the overall design process of the turbofan engine, it has become crucial to address the challenge of selecting design parameters that not only meet the flight thrust demand but also enhance engine economy. As the demand for stealth performance in future fighter aircraft increases, it becomes imperative to consider infrared stealth indicators during the design process. The adaptive cycle engine possesses an adjustable thermal cycle, necessitating careful attention to the selection of design parameters to fulfill the requirements. Therefore, this paper proposes a multi-objective optimization design method for the adaptive cycle engine that integrates infrared stealth technology. Initially, the parameter cycle model of the adaptive cycle engine is established based on the principles of aerodynamic and thermodynamic calculations. Subsequently, the model incorporates a serpentine two-dimensional (2-D) exhaust system to achieve infrared suppression. Meanwhile, a method for predicting the infrared characteristics is proposed to calculate the infrared radiation intensity of the engine exhaust system. Finally, the sequential quadratic programming algorithm is applied to comprehensively optimize the engine's performance. The simulation results reveal that the multi-objective optimization design can effectively select appropriate design parameters to im-prove the engine, thereby reducing fuel consumption while meeting thrust requirements. This approach combines the consideration of infrared stealth technology with the optimization of engine performance, thus contributing to the development of advanced adaptive cycle engines. [ABSTRACT FROM AUTHOR]

The design and preparation of infrared stealth materials that meet the application in complex environments is urgently demanded in military fields. In this paper, composites with low emissivity and thermal insulation are designed to be used for indoor and outdoor infrared stealth. Thereinto, nanoPE-MXene, yttrium oxide coated hollow glass microspheres (HGMs@Y 2 O 3) and polypropylene nonwoven (PPF) were used as low emission, insulation, and antifouling layers, respectively. The sandwich-structured composite reduce the infrared radiation temperature of the 80 °C heat source object to 33.9 °C , and the average infrared emissivity of 3-15 μm is only 0.17. In addition, the infrared stealth performance of the composite is not affected by environmental changes. More importantly, the composite exhibits excellent anti-fouling and ageing resistance performance, which lays the foundation for the practical application of efficient stealth infrared materials. [ABSTRACT FROM AUTHOR]

The ability to selectively emit in specific spectral bands, known as spectral selective emission, is highly valuable in thermal photovoltaic systems, infrared stealth, radiation heat dissipation, and other fields. This paper presents a planarized molybdenum/zinc sulfide (Mo/ZnS) multilayer film design to achieve infrared stealth under high temperatures. By utilizing the distinctive radiation characteristics of an ultra-thin Mo layer and impedance matching, selective emission in the infrared band can be achieved. The fabricated multilayer films have low emissivity in the atmospheric window (ε(3–5μm) = 0.19; ε(8–14μm) = 0.29), but high emissivity in the non-atmospheric window (ε(5–8μm) = 0.7). In addition to ensuring infrared stealth performance, the films can also withstand high temperatures up to 723K with good high-temperature resistance. Moreover, the proposed design has several advantages, including structural simplicity, ductility, and ease of mass production. This work could bring added convenience to many applications, including infrared stealth, in the future.

[Display omitted] Alongside the rapid development of detection systems and improved detection accuracy, infrared/radar-compatible stealth materials have become the emphasis of current stealth technology research. Versatile flower-like Ni particles/silicon carbide nanowires (SiC NWs) composites for infrared radar stealth compatibility have been successfully prepared. Due to its special microstructure in combination with the multiple loss mechanisms of dielectric and magnetic, the minimum reflection loss (RL min) achievable with the paraffin matrix mixture is −49.26 dB at a composite content of 50 wt%, which has a thickness of 1.9 mm and an effective absorption bandwidth (EAB) of 4.85 GHz. By increasing the absorbent content to 60 wt%, the EAB in the Ku band can attain 5.0 GHz at 1.8 mm thickness. Petal-shaped Ni particles are introduced to improve the impedance matching characteristics, increase interfacial polarisation and multiple scattering of electromagnetic (EM) wave, and enhance the microwave absorption properties. Simultaneously, the pure SiC NWs material can protect against infrared radiation emitted from the hand for more than 15 min, and the infrared (IR) reflectivity is improved in all three bands after the composite metal Ni particles. A novel formulation guide for the design of versatile and high-performance EM wave absorbing and infrared stealth materials is provided by this work. [ABSTRACT FROM AUTHOR]

Multifunctional microwave absorbing materials with properties of high absorbing performance, infrared stealth, thermal insulation are urgently required to cope with current complex and extreme electromagnetic environment. To solve this problem, a three-dimensional carbon foam (CF) was used as a matrix, and Fe/C nanocubes derived from Prussian Blue (PB) were uniformly distributed throughout the CF skeleton. Such design of Fe/C/CF porous structures enhanced the synergistic effects between dielectric and magnetic loss to reach a better absorbing performance. The minimum reflection loss (RL) of hybrid foam is −66.7 dB, and the widest effective absorbing bandwidth (EAB, RL < −10dB) is 6.34 GHz. Moreover, the hybrid foam showed remarkable infrared stealth and thermal insulation properties. The surface temperature of hybrid foam almost unchanged while it was heated under 100 °C for more than 1 h. It is noteworthy that the preparation process of hybrid foam was a facile, recycled, and low-cost strategy for achieving high-performance absorbing materials. Besides, the mentioned methods may provide inspirations for the preparation of high-performance microwave absorbing materials and increase the potential application fields in complex actual scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

Infrared selective emitters are attracting more and more attention due to their modulation ability of infrared radiance, which provides an efficient ability to blend objects into the surrounding environment. In this paper, an Ag/ZnS/Si/Ag/Si multilayered emitter is proposed by virtue of impedance matching as well as Fabry-Perot cavity effect to achieve selective radiation in the infrared band. The emissivity of the fabricated selective emitter is measured to be ε3–5μm = 0.16 and ε8–14μm = 0.23 in the atmosphere windows, respectively, meeting the requirements of infrared stealth. Meanwhile, the emissivity at the non-atmospheric window (5–8 μm) is as high as 0.78, which allows efficient heat dissipation to achieve radiative cooling. Furthermore, the selective emitter maintains excellent stealth performance until 350 °C, indicating its good heat resistance and dissipation at medium temperature. The proposed emitter with spectral selectivity provides a new strategy for the facile fabrication of mid-/low-temperature infrared stealth devices. [ABSTRACT FROM AUTHOR]

We report a complementary metal oxide semiconductor (CMOS) compatible metamaterial-based spectrally selective absorber/emitter (MBSSAE) for infrared (IR) stealth, which has the low absorption/emissivity in the IR atmospheric transmission window (3 µm–5 µm, 8 µm–14 µm) and ultra-high and broadband absorption/emissivity in the IR non-atmospheric window (5 µm–8 µm). We propose a novel method for the broadband absorption/emissivity in 5 µm–8 µm with incorporation of an epsilon-near-zero (ENZ) material between the top patterned aluminum (Al) disks layer and the silicon oxide (SiO2) spacer layer. With an appropriate design, the peaks in the IR atmospheric transmission window can be suppressed while the peak intensity in the non-atmospheric window remains high. The optimized MBSSAE has an average absorption/emissivity less than 10% in 8 µm–14 µm and less than 6% in 3 µm–5 µm. And the average absorption/emissivity in 5 µm–8 µm is approximately over 64%. This proposed scheme may introduce the opportunities for the large-area and low-cost infrared stealth coating, as well as for the radiative cooling, spectral selective thermal detector, optical sensor, and thermophotovoltaic applications. [ABSTRACT FROM AUTHOR]

Abstract We report a complementary metal oxide semiconductor (CMOS) compatible metamaterial-based spectrally selective absorber/emitter (MBSSAE) for infrared (IR) stealth, which has the low absorption/emissivity in the IR atmospheric transmission window (3 µm–5 µm, 8 µm–14 µm) and ultra-high and broadband absorption/emissivity in the IR non-atmospheric window (5 µm–8 µm). We propose a novel method for the broadband absorption/emissivity in 5 µm–8 µm with incorporation of an epsilon-near-zero (ENZ) material between the top patterned aluminum (Al) disks layer and the silicon oxide (SiO2) spacer layer. With an appropriate design, the peaks in the IR atmospheric transmission window can be suppressed while the peak intensity in the non-atmospheric window remains high. The optimized MBSSAE has an average absorption/emissivity less than 10% in 8 µm–14 µm and less than 6% in 3 µm–5 µm. And the average absorption/emissivity in 5 µm–8 µm is approximately over 64%. This proposed scheme may introduce the opportunities for the large-area and low-cost infrared stealth coating, as well as for the radiative cooling, spectral selective thermal detector, optical sensor, and thermophotovoltaic applications.

Simultaneously developing protective electronics film for multi‐spectra, including the radar, infrared (IR), and visible ranges, for both the military and civilian sectors is extremely challenging. The existing multi‐spectra‐compatible materials mainly concentrate on either the radar/IR or IR/visible bands, trailing the rapid evolution of advanced devices for monitoring electromagnetic signals. Here, it is designed and fabricated an ultra‐thin MXene‐based composite film (20 µm) containing black phosphorus (BP) and Ni chains (M‐B‐M(Ni)) with integrated highly efficient thermal IR stealth, visible light absorption, and electromagnetic wave shielding. M‐B‐M(Ni) exhibits an extremely low IR emissivity of 0.1, decreasing the radiation temperature difference between the surrounding environment and target device. BP offers a high solar absorptance of 80%, which guarantees energy conversion from visible light to heat. Moreover, the absorption proportion of the electromagnetic shielding effectiveness for M‐B‐M(Ni) is 16% higher than that of pure MXene films (68.7%), owing to the improved magnetic loss by decoration with magnetic Ni chains. Due to the combined merits of MXene, BP, and Ni chains, M‐B‐M(Ni) opens an avenue for the construction of advanced multi‐spectra compatible materials for versatile applications in thermal IR stealth, electromagnetic wave shielding, and energy transformation. [ABSTRACT FROM AUTHOR]

The rapid development of surveillance technology has driven the research of multispectral stealth. Demand for infrared and microwave radar compatible stealth is becoming increasingly urgent in military applications. Herein, a versatile metamaterial absorber is designed and fabricated to simultaneously achieve ultra-broadband radar scattering reduction, low infrared emission, and high optical transparency. The designed structure consists of an infrared stealth layer, radar absorption layers, and backing ground. The infrared stealth layer employs specifically indium tin oxide (ITO) square patches, while the radar absorption layers can be obtained by stacking different size ITO patterned films of the same structure with high surface resistances, realizing broadband microwave stealth performance in the 1.98–18.6 GHz frequency range with an incident angle of 45°. The broad radar stealth and low infrared emissivity of 0.283 are consistent with the simulations and calculations. Furthermore, the designed structure exhibits characteristics such as polarization insensitivity, wide incident angles, optical transparency, and flexibility, allowing for a wide range of applications in various environments. [ABSTRACT FROM AUTHOR]

Infrared (IR) stealth plays a vital role in the modern military field. With the continuous development of detection technology, multi-band (such as near-IR laser and middle-IR) compatible IR stealth is required. Combining rigorous coupled wave analysis (RCWA) with Deep Learning (DL), we design a Ge/Ag/Ge multilayer circular-hole metasurface capable of multi-band IR stealth. It achieves low average emissivity of 0.12 and 0.17 in the two atmospheric windows (3~5 μm and 8~14 μm), while it achieves a relatively high average emissivity of 0.61 between the two atmospheric windows (5~8 μm) for the purpose of radiative thermal management. Additionally, the metasurface has a narrow-band high absorptivity of 0.88 at the near-infrared wavelength (1.54 μm) for laser guidance. For the optimized structure, we also analyze the potential physical mechanisms. The structure we optimized is geometrically simple, which may find practical applications aided with advanced nano-fabrication techniques. Also, our work is instructive for the implementation of DL in the design and optimization of multifunctional IR stealth materials. [ABSTRACT FROM AUTHOR]

Microwave and infrared–thermal radiation-compatible shielding fabrics represent an important direction in the development of wearable protective fabrics. Nevertheless, effectively and conveniently integrating compatible shielding functions into fabrics while maintaining breathability and moisture permeability remains a significant challenge. Here, we take hydrophilic PVA-co-PE nanofibrous film-coated PET fabric (NFs/PET) as a flexible substrate and deposit a dielectric/conductive (SiO2/Al) bilayer film via magnetron sputtering. This strategy endows the fabric surface with high electrical conductivity, nanoscale roughness comparable to visible and infrared waves, and a dielectric–metal contact interface possessing localized plasmon resonance and Mie scattering effects. The results demonstrate that the optimized SiO2/Al/NFs/PET composite conductive fabric (referred to as S4-1) possesses favorable X-band electromagnetic interference (EMI) shielding effectiveness (50 dB) as well as excellent long-wave infrared (LWIR) shielding or IR stealth performance (IR emissivity of 0.60). Notably, the S4-1 fabric has a cooling effect of about 12.4 °C for a heat source (80 °C) and an insulating effect of about 17.2 °C for a cold source (−20 °C), showing excellent shielding capability for heat conduction and heat radiations. Moreover, the moisture permeability of the S4-1 fabric is about 300 g/(m2·h), which is better than the requirement concerning moisture permeability for wearable fabrics (≥2500–5000 g/(m2·24 h)), indicating excellent heat and moisture comfort. In short, our fabrics have lightweight, thin, moisture-permeable and excellent shielding performance, which provides novel ideas for the development of wearable multi-band shielding fabrics applied to complex electromagnetic environments.

Current research on multispectral stealth material technology focuses on practical functionalities such as optical transparency, flexibility, and lightweight. Herein, an optically transparent and single‐layer frequency‐selective surface (OTSF) absorber for dual‐band millimeter‐wave (MMW) absorption and low‐infrared (IR) emissivity is proposed. By adopting indium tin oxide and polyethylene terephthalate, the proposed OTSF absorber exhibits good optical transparency (76% transmittance in the 400–800 nm range on an average) and flexibility. The OTSF absorber exhibits high absorption at the dual‐band frequency in the MMW range (99.7% at 35 GHz and 89.7% at 103 GHz). In the IR band, the average band emissivity of the OTSF absorber for the midwave IR (MWIR) band (3–8 μm) and the long‐wave IR (LWIR) band (8–15 μm) is measured to be 0.26 and 0.23, respectively. Thermal images of the OTSF absorber clearly show its low‐emission characteristics that are similar to those of metal. The proposed OTSF absorber structure has significant potential for practical applications of MMW–IR multispectral stealth materials.

The development of high-performance and multi-modal stealth materials remains a challenge. Herein, nickel nanoparticles embedded in three-dimensionally ordered macro-/mesoporous carbon framework (Ni/OMMC) was fabricated using a facile dual-template approach to achieve efficient microwave absorption and multi-functions. It is found that the carbonization temperature in the preparation process of Ni/OMMC has significant influence on the electromagnetic properties of samples. The optimized microwave absorption performance was achieved by adjusting the calcination temperature to 900 °C. It shows that the minimum reflection loss (RL min) for Ni/OMMC900 reaches −43.6 dB at 5.0 GHz with a thickness of only 2.0 mm, and effective absorption bandwidth of 5.6 GHz at 1.0 mm with the ultra-low filling ratio of only 3%. Its excellent microwave absorption performance may be attributed to enhanced conductive loss, polarization relaxation and magnetic loss, and impedance matching, which result from magnetic/conductive multi-component synergy and the unique 3D interconnected hierarchically porous structure. Additionally, Ni/OMMC900 exhibits good thermal insulation and infrared stealth functions. [Display omitted] • Ni nanoparticles in situ embedment in 3D ordered macro-/mesoporous carbon was fabricated for the first time. • The Ni/OMMC has large specific surface and high porosity. • The RL min of −43.6 dB and EAB of 5.0 GHz were achieved at an ultra-low filling ratio of 3%. • The Ni/OMMC has radar-infrared bi-modal stealth functions. [ABSTRACT FROM AUTHOR]

Achieving multifunctionality to broaden the application scenarios is the development direction of electromagnetic wave (EMW) absorbing materials in the future. Here, a waterproof magnetic carbon foam (CF) was successfully prepared using a simple high-temperature pyrolysis and dip coating process, where the magnetic Fe 3 O 4 nanoparticles were homogeneously and tightly encapsulated on the carbon skeleton of CF with the help of low surface energy PDMS, achieving the expected high-efficient EMW absorption performance. Except the 3D porous structure that contributes stronger EMW absorption through multi-reflection and scattering, the coexistence of conductive carbon skeleton and magnetic Fe 3 O 4 can supply the dielectric-magnetic dual-loss, which is also beneficial for better impedance matching. In addition, the amounts of heterointerfaces and abundant crystalline defects and doped N atoms in graphitic carbon can also generate additional polarization loss. Furthermore, high-efficient EMW absorption capacity was achieved by tuning the pyrolysis temperature, of which the CF pyrolyzed at a temperature of 900 °C (PDMS/Fe 3 O 4 /CF-900) exhibited a minimum reflection loss (RL min) value of −47.36 dB with 3.15 mm thickness and a maximum effective absorption bandwidth (EAB max) up to 9.76 GHz with 4.2 mm thickness. What's more, combining with the merits of high conductivity, hydrophobicity, and special 3D porous structure, the expected multifunctionality was also successfully achieved for the prepared PDMS/Fe 3 O 4 /CF-900, where it displays the excellent thermal management performance including a high Joule heating temperature of 161 °C at only 5 V and reliable heating capacity over 1500 s, high-efficient oil-water separation capacity such as high absorption amount (45.58 times), rapid absorption (1.14 s), and stable cyclic adsorption-desorption performances, and great thermal insulation property with a temperature difference up to 219.9 °C that make it to be promising infrared stealth material. This work provides a feasible strategy for the rational design and application of novel lightweight multifunctional high-performance EMW absorbing materials. [Display omitted] • Magnetic carbon foam was prepared for multifunctional EMW absorbing material. • The foam displays a RL min of −47.36 dB and wide EAB of 9.76 GHz. • The foam possesses great potential in the field of personal thermal management. • The foam can be applied for infrared stealth of military equipment. [ABSTRACT FROM AUTHOR]

The sandwich structure composite was prepared by the specific procedure, as stated below: first, Hollow glass microspheres (HGMs)/thermoplastic polyurethane (TPU) composite was prepared by mixing HGMs and TPU solvent and curing for 1 h; subsequently, polyacrylonitrile (PAN)/SiO2 membrane was spun onto the surface composite by electrospinning; And besides, the Ag mirror was prepared by the magnetron sputtering system. It was confirmed that the thin composite acquired superior thermal insulation and mechanical properties. Furthermore, the infrared stealth function of this thermal insulation was also studied systematically. Significantly, the facile-produce has a potential to be applied as thermal insulation and infrared stealth materials in industrial application. [ABSTRACT FROM AUTHOR]

Fabric-based infrared (IR) stealth composites with thermal insulation and low emissivity are desirable for improving IR camouflage of military targets and thermal management of special environments. Therefore, a flexible and foldable composite fabric with a sandwich structure is delicate designed in this work aiming to realize dual-modes IR effects. Polyester fabric chemically plated with copper-nickel (Cu/Ni@PF) and aluminum foil (AF) are on the top and bottom, respectively, acting as low emissivity layers. The medium layer is constructed by silica aerogel microspheres (SAM) with thickeners and waterborne polyurethanes (WPU) functioned as thermal insulation. The thermal conductivity of as-prepared composite fabric is only 0.05904 W/(m·K). When the AF is heated to 70 °C, the introduction of the SAM in the medium layer with the thickness of 300 μm makes Cu/Ni@PF as top surface exhibit a obvious temperature difference of 11.7 °C, demonstrating excellent thermal insulation. The AF maintains a low emissivity of less than 0.2, and the emissivity of Cu/Ni@PF was also as low as 0.296 at 8–14 μm, which can effectively shield the IR signal. Thanks to the Cu/Ni@PF as the top surface, the radiation temperature displays only 36.3 °C when heated at 70 °C, which meaning the dramatic IR signal strength reduce. Therefore, this dual-modes flexible and foldable composite can be a potential candidate in the IR stealth fields. • Chemical plating method is introduced to polyester fabric performs excellent in low emissivity. • SiO 2 microspheres prepared by sol-gel method and emulsion spheronisation show good property in thermal insulation. • A sandwich structure composites with multi-module cooperation can lead to a better effect in IR stealth. [ABSTRACT FROM AUTHOR]

[Display omitted] • EMI shielding paper is constructed with corrugated paper-like structure. • Aerogel film in-between two conductive papers enhances the EMI shielding performance. • The corrugated paper-like structure remarkably decreases the conductive filler (MXene) dosage. • The composite paper also exhibits infrared stealth and joule heating properties. The structural design of material significantly influences its electromagnetic interference (EMI) shielding performance, providing an intelligent approach to attain desirable EMI shielding performances. Inspired by the ultra-large distance of the middle layer in corrugated paper, we proposed a novel composite paper with corrugated paper-like structure via the assembling of two pieces of surface-modified filter paper and an aerogel film. Specifically, a conventional filter paper was modified with the conductive hydrogel film consisting of TEMPO-oxidized cellulose nanofibers (TOCNF), cationic starch (CS) and Ti 3 C 2 T x. The TOCNF and CS rapidly formed a composite hydrogel when mixed, due to their electrostatic interactions. The aforementioned aerogel film was produced through the freeze-drying of TOCNF/CS hydrogel, and it enlarged the distance between two conductive hydrogel film modified papers when inserted. The assembled composite papers demonstrated a maximum EMI SE of 71.0 dB, improved by 19.7 % as compared to the control without the aerogel film (59.3 dB). The expansion of the distance between conductive layers likely facilitated the enhancement in the multiple reflections and absorptions of electromagnetic waves. This novel composite paper showed better EMI shielding performance than many previously-reported materials considering the thickness and conductive filler dosage. In addition, the composite paper also showed exceptional infrared stealth capabilities since it effectively shielded the thermal radiation from human body. The composite paper still exhibited good infrared stealth ability at high temperature conditions (up to 120 ℃). Therefore, this research could inspire innovative concepts in designing high-performance and multifunctional EMI shielding materials in an economical way. [ABSTRACT FROM AUTHOR]

• Water immerse-stacking assembly fabricates 3D aerogel membranes. • Aerogel membranes enhance thermal insulation and mechanical strength. • MXene nanosheets are firmly embedded into nanofibers via vacuum-assisted filtration. • 1 mm thick aerogel membranes reduce 300 °C object radiation temperature by 206 °C. • Aerogel membrane flexibility creates outstanding infrared stealth bags. The development of high-performance infrared stealth materials has been a long-standing goal for scientists. Despite their excellent performance, these materials are challenging to fabricate. In this work, a simple water immerse-stacking assembly process is employed to transform two-dimensional nanofiber membranes into three-dimensional aerogel membranes. Directional freezing from different directions induced varied orientations in the polyimide nanofibers (PINF), leading not only to unique anisotropic microstructures and thermal conductivities but also to synergistic enhancements in thermal insulation and mechanical properties. By vacuum-assisted filtration, MXene is embedded into the PINF membrane, resulting in a low emissivity of 0.283 and strong interlayer bonding of the MXene/PINF aerogel membrane without affecting the high and low-temperature resistance, the tensile strength, and the flexibility. Inspired by the art of origami, two types of MXene/PINF aerogel membrane bags are developed. When using one of the bags to cover an object at 130.2 °C, the thermal radiation temperature decreases to 28.9 °C. This study provides a promising approach for designing flexible, high-strength, and efficient infrared stealth composite materials, paving the way for further research and applications. [ABSTRACT FROM AUTHOR]

• A spectrally selective radiation infrared stealth metafilm based on a simple bilayer structure is proposed and experimentally demonstrated. • The metafilm uses the common inexpensive metal Mo instead of traditional precious metals and can be easily fabricated. • The metafilm achieves infrared stealth with low emissivity in the atmospheric window and radiation heat dissipation with high emissivity in the non-atmospheric window. In this paper, we propose and demonstrate a spectrally selective radiation infrared stealth metafilm based on a simple bilayer structure. Specifically, we use the common inexpensive metal Mo instead of traditional precious metals and achieve selective thermal radiation in the infrared band. In the atmospheric window band, the absorptivity is relatively low, which can well achieve the purpose of infrared stealth, while in the non-atmospheric window band, the absorptivity acutely increases, with a high absorptivity of 94.89 % at 6.04 μ m , which can achieve better radiation heat dissipation. The experimental results are consistent with the simulation. The average emissivity in the 8–14 μ m atmospheric window band is 0.32, while in the 5–8 μ m non-atmospheric window band is 0.80, which proves the possibility of its practical application. Meanwhile, the metafilm proposed by us can be easily fabricated and can be widely used in the control of infrared thermal radiation, thermal management, and thermal camouflage, which has a very promising application prospect. [ABSTRACT FROM AUTHOR]

In this paper, a composite film with a thickness of 0.25 mm was prepared, which has the functions of infrared stealth, ultraviolet protection, sound absorption, and thermal insulation. Firstly, polyaniline was synthesized through chemical oxidative polymerization using aniline as a monomer, acetic acid as a dopant, and ammonium persulfate as an oxidant. Then, the synthesized polyaniline (PANI), hollow glass beads (HGB), and carbon fiber powder (CFP) were sequentially added to waterborne polyurethane, and a film coating machine was used to prepare a multifunctional composite film of PANI/HGB/CFP. Finally, the composite film's infrared properties, ultraviolet protection properties, sound absorption properties, thermal constants, resistance to water penetration properties, bending properties, tensile properties, chemical corrosion resistance, and aging resistance were tested. The results show that the prepared PANI/HGB/CFP composite film has an infrared emissivity of 0.668 and an ultraviolet protection factor (UPF) of 1072, indicating that it can block more than 99 % of ultraviolet rays. Additionally, it has an acoustic absorption coefficient of 0.386. At the same time, the thermal conductivity is 0.04629 W/mK, making it a highly efficient material for heat preservation and thermal insulation. The prepared PANI/HGB/CFP composite film is expected to be a new multifunctional military tarpaulin. [Display omitted] • PANI/HGB/CFP composite film was prepared by adding polyaniline, hollow glass beads, and carbon fiber powder into WPU. • PANI/HGB/CFP composite film has infrared stealth, ultraviolet protection, sound absorption, thermal insulation, and so on. • PANI/HGB/CFP composite film is applied to military tarpaulins, which can ensure the smooth operation of military equipment. [ABSTRACT FROM AUTHOR]

In the overall design process of the turbofan engine, it has become crucial to address the challenge of selecting design parameters that not only meet the flight thrust demand but also enhance engine economy. As the demand for stealth performance in future fighter aircraft increases, it becomes imperative to consider infrared stealth indicators during the design process. The adaptive cycle engine possesses an adjustable thermal cycle, necessitating careful attention to the selection of design parameters to fulfill the requirements. Therefore, this paper proposes a multi-objective optimization design method for the adaptive cycle engine that integrates infrared stealth technology. Initially, the parameter cycle model of the adaptive cycle engine is established based on the principles of aerodynamic and thermodynamic calculations. Subsequently, the model incorporates a serpentine two-dimensional (2-D) exhaust system to achieve infrared suppression. Meanwhile, a method for predicting the infrared characteristics is proposed to calculate the infrared radiation intensity of the engine exhaust system. Finally, the sequential quadratic programming algorithm is applied to comprehensively optimize the engine’s performance. The simulation results reveal that the multi-objective optimization design can effectively select appropriate design parameters to im-prove the engine, thereby reducing fuel consumption while meeting thrust requirements. This approach combines the consideration of infrared stealth technology with the optimization of engine performance, thus contributing to the development of advanced adaptive cycle engines.