Abstract
Electromagnetic (EM) and infrared (IR) stealth play an important role in the development of military technology and the defense industry. This study focused on developing a new type of multifunctional composite film based on polyimide (PI)/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) as a phase change material (PCM) for EM and IR bi-stealth applications. The composite films were successfully fabricated by constructing a series of PI-based hybrid aerogels containing different contents of graphene nanosheets and Fe3O4 nanoparticles through prepolymerizaton, film casting, freeze-drying, and thermal imidization, followed by loading molten PEG through vacuum impregnation. The construction of PI/graphene/Fe3O4 hybrid aerogel films provides a robust, flexible, and microwave-absorption-functionalized support material for PEG. The resultant multifunctional composite films not only exhibit high microwave absorption effectiveness across a broad frequency range, but also show a good ability to implement thermal management and temperature regulation under a high latent-heat capacity of over 158 J/g. Most of all, the multifunctional composite films present a wideband absorption capability at 7.0–16.5 GHz and a minimum reflection loss of −38.5 dB. This results in excellent EM and IR bi-stealth performance through the effective wideband microwave absorption of graphene/Fe3O4 component and the thermal buffer of PEG. This study offers a new strategy for the design and development of high-performance and lightweight EM–IR bi-stealth materials to meet the requirement of stealth and camouflage applications in military equipment and defense engineering.
Highlights
IntroductionStealth technologies are a combination of technologies that attempt to make military equipment and vehicles, mostly aircraft, less visible or ideally invisible to radar, infrared, sonar, and other detection methods, leading to a practical form of active camouflage [1]
These Fe3 O4 nanoparticles are well dispersed on the graphene surface without any agglomerations, indicating that the graphene nanosheets act as a framework and network to support and separate the loaded Fe3 O4 nanoparticles
We have developed a novel type of multifunctional phase-change comIn summary, we have developed a novel type of multifunctional phase-change composite films based on PI/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) for EM and IR bi-stealth posite films based on PI/graphene/Fe
Summary
Stealth technologies are a combination of technologies that attempt to make military equipment and vehicles, mostly aircraft, less visible or ideally invisible to radar, infrared, sonar, and other detection methods, leading to a practical form of active camouflage [1]. Stealth technology was initially developed for aircraft by using transparent materials or painting with light colors to reduce “visibility” before RADAR was invented. The development of stealth technology through employing every available method to avoid detection by visible, RADAR, infrared (IR), and acoustic means has attracted tremendous attention in the fields of military science and defense technology, especially for new weapons and military equipment [3]. RADAR is the use of reflected electromagnetic (EM) waves in the microwave part of the spectrum to detect targets or map landscapes, whereas IR sensors or thermal imaging cameras can only detect and visualize the targets that have IR radiance
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