Review on recent progress in epoxy‐based composite materials for Electromagnetic Interference(EMI) shielding applications

Abstract

The densely packed electronic components in electronic devices emit electromagnetic (EM) radiations, and the interaction of the emitted EM radiations with external EM signals of neighboring components leads to device malfunctions and also creates health issues in human beings. Particularly, in aircraft, EM interference is a serious threat that leads to disastrous outcomes. The shielding of electronic components is an ideal way to reduce the pollution of electromagnetic interference (EMI). The mechanism of EMI shielding efficiency is discussed elaborately in this article. The factors associated with the EMI shielding of materials are discussed in detail. The EMI shielding by reflection and absorption are two possible routes to improve the shielding performance of the shielding materials. This article also highlights the EMI shielding mechanisms by reflection and absorption. However, the risk of secondary EM pollution is associated with the reflection of EM waves. This review also outlines the methods to improve the absorption‐based shielding performance of the materials. The significance of the microstructure of the shielding materials in enhancing the absorption‐dominant shielding efficiency is also presented with a detailed analysis. This helps to fabricate the absorption‐dominant EMI shielding materials with suitable microstructures. The EM loss is associated with the magnetic, dielectric, and conduction losses according to EM theory.Highlights This article highlights the recent progress in epoxy‐based EMI shielding materials. EMI shielding mechanisms by reflection and absorption are discussed elaborately. Reviewed the methods to improve the absorption‐based shielding performance in detail. Materials with EMI shielding efficiency greater than 30 dB are highly preferable.

PVDF/Fe3O4@pDA@Ag Nanofiber Membranes with Multicore–Shell Structure for EMI Shielding

“…The application of magnetic nanofillers in enhancing the EMI shielding performance of NFMs has been widely reported. This is because their quantum size effect, natural resonance, and microcurrent properties can improve the magnetic loss and electromagnetic shielding performance of composite NFMs. − In the work of Yang et al, a bifunctional electrospun NFM (33 μm thickness) was reported, whose surface was modified with Fe 3 O 4 nanoparticles (NPs) and MXene nanosheets, demonstrating an excellent specific shielding efficiency (SE) of 9212.1 dB cm 2 g –1 in the 8–26.5 GHz frequency range. Anwar et al used electrospinning technology to synthesize CoFe 2 O 4 /C NFMs, with an EMI SE of 30–35 dB.…”

MXene Composite Electromagnetic Shielding Materials: The Latest Research Status

“…However, conventional electromagnetic shielding materials primarily rely on reflecting electromagnetic waves, leading to the propagation of a large amount of reflected electromagnetic waves in space, which may continue to interfere with unshielded devices, resulting in secondary electromagnetic wave pollution. 8 Despite the extensive application of traditional metal materials in the field of electromagnetic shielding, they have some inherent limitations. For instance, their considerable weight and volume restrict the lightweight design in portable or wearable devices; their high rigidity makes them difficult to bend or shape, which is not conducive to achieving flexible or customized shielding solutions; the difficulty in processing increases manufacturing costs and time; they are susceptible to corrosion, which reduces shielding effectiveness and may cause secondary pollution; impedance matching issues lead to increased reflection of electromagnetic waves, affecting the shielding effect; high surface reflection rates increase the possibility of secondary reflection; they have single functions, mainly providing shielding effects without other additional functions; and poor environmental adaptability, which can lead to performance degradation under extreme conditions.…”

“…Electromagnetic shielding materials typically block electromagnetic wave propagation by either reflecting incident electromagnetic waves or absorbing the electromagnetic wave energy entering the material and converting it into heat, gradually dissipating energy and reducing the penetration rate of electromagnetic waves. However, conventional electromagnetic shielding materials primarily rely on reflecting electromagnetic waves, leading to the propagation of a large amount of reflected electromagnetic waves in space, which may continue to interfere with unshielded devices, resulting in secondary electromagnetic wave pollution . Despite the extensive application of traditional metal materials in the field of electromagnetic shielding, they have some inherent limitations.…”