Flexible Electromagnetic Interference Research Articles

Flexible Sandwich-Structured Electromagnetic Interference Shielding Nanocomposite Films with Excellent Thermal Conductivities.

With the rapid development and popularization of smart, portable, and wearable flexible electronic devices, urgent demands have been raised for flexible electromagnetic interference (EMI) shielding films to solve related electromagnetic pollution problems. With polyvinyl alcohol (PVA) as polymer matrix, the sandwich-structured EMI shielding nanocomposite films are prepared via electrospinning-laying-hot pressing technology, where Fe3 O4 /PVA composite electrospun nanofibers in the top and bottom layers and Ti3 C2 Tx /PVA composite electrospun nanofibers in the middle layer. Owing to the electrospinning process and the successful construction of the sandwich structure, when the amounts of Ti3 C2 Tx and Fe3 O4 are respectively only 13.3and 26.7wt%, the EMI shielding effectiveness (EMI SE) of the sandwich-structured EMI shielding nanocomposite films reach 40 dB with the thickness of 75 µm, higher than that of (Fe3 O4 /Ti3 C2 Tx )/PVA EMI shielding nanocomposite films (21 dB) prepared based on blending-electrospinning-hot pressing process under the same amounts of fillers. Furthermore, the prepared sandwich-structured EMI shielding nanocomposite films possess excellent thermal conductivities and mechanical properties. This novel kind of flexible sandwich-structured EMI shielding nanocomposite films with excellent EMI shielding performances, thermal conductivities, and mechanical properties presents broad application prospects in the fields of EMI shielding and protection for high-power, portable, and wearable flexible electronic devices.

Flexible and transparent silver nanowires/biopolymer film for high-efficient electromagnetic interference shielding

Flexible and transparent conductive films are highly desirable in some optoelectronic devices, such as smart windows, touch panels, as well as displays and electromagnetic protection field. Silver nanowire (Ag NW) has been considered as the best material to replace indium tin oxide (ITO) to fabricate flexible transparent electromagnetic interference (EMI) shielding films due to its superior comprehensive performance. However, the common substrates supporting Ag NWs require surface modification to enhance the adhesion with Ag NWs. In this work, a flexible and transparent Ag NWs EMI shielding film with sandwich structure through a facile rod-coating method, wherein Ag NWs network were embedded between biodegradable gelatin-based substrate and cover layer. The interfacial adhesion between Ag NWs and gelatin-based layers was enhanced by hydrogen-bonding interaction and swelling effect without any pretreatment. The shielding effectiveness (SE) of the G/Ag NW/G (G represents gelatin-based layer) film reaches 37.74 dB at X band with an optical transmittance of 72.0 %. What’s more, the flexible gelatin-based layer and encapsulated structure endow the resultant G/Ag NW/G film integrating excellent mechanical properties, reliable durability, antioxidation, as well as anti-freezing performance. This work paves a new way for fabricating flexible transparent EMI shielding films.

Effective lightweight, flexible and ultrathin PVDF/rGO/Ba2Co2Fe12O22 composite films for electromagnetic interference shielding applications

In this study, we developed a simple and cost-effective solvent film casting method to fabricate ultrathin, flexible and lightweight polyvinylidenefluoride (PVDF)-based composites that provide high electromagnetic interference (EMI) shielding performance. Y-type barium hexaferrite with general formula Ba2Co2Fe12O22 was first synthesized by the sol–gel autocombustion method and then reduced graphene oxide (rGO) was prepared by modified Hummer’s method. The crystal structure, morphology, elemental surface analysis and magnetic properties of the samples were systematically investigated using x-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, high-resolution scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometry. Then, the complex permittivity, complex permeability and EMI shielding properties of the flexible PVDF/rGO/Ba2Co2Fe12O22 composite films with two different amounts of Ba2Co2Fe12O22 NP content and a fixed amount of rGO content were investigated using a vector network analyzer. The structural characterizations of the resultant composite films showed the formation of an electroactive β-phase of PVDF with addition of Ba2Co2Fe12O22 nanoparticles and rGO content. The enhancement of the β-phase in the PVDF/rGO/Ba2Co2Fe12O22 nanocomposites was explained from a physicochemical viewpoint. Furthermore, the electrically conductive and magnetic properties of PVDF composite films incorporating rGO and Ba2Co2Fe12O22 NPs exhibited a high EMI shielding effectiveness of 25.63 dB, with an absorption-dominated shielding feature in the 8–12 GHz region. The enhanced absorption was attributed to the electrostatic interaction induced by the β-phase fraction in the PVDF matrix, and subsequently from multiple reflections and magnetic loss originating from the synergetic effect of rGO and Ba2Co2Fe12O22 NPs. This study introduces a low-cost and scalable method for the design of novel, lightweight, flexible and efficient EMI shielding composite films with promising prospects for application in the construction, electronics and aerospace fields.

Polymeric textile-based electromagnetic interference shielding materials, their synthesis, mechanism and applications – A review

The rapid proliferation of electronic devices and their operation at high frequencies has raised the contamination of artificial electromagnetic radiations in the atmosphere to an unprecedented level that is responsible for catastrophe for ecology and electronic devices. Therefore, the lightweight and flexible electromagnetic interference (EMI) shielding materials are of vital importance for controlling the pollution generated by such high-frequency EM radiations for protecting ecology and human health as well as the other nearby devices. In this regard, polymeric textile-based shielding composites have been proved to be the best due to their unique properties such as lightweight, excellent flexibility, low density, ease of processability and ease of handling. Moreover, such composites cover range of applications from everyday use to high-tech applications. Various polymeric textiles such as fibers, yarn, woven, nonwoven, knitted, as well as their hybrid composites have been extensively manipulated physically and/or chemically to act as shielding against such harmful radiations. This review encompasses from basic concept of EMI shielding for beginner to the latest research in polymeric-based textile materials synthesis for experts, covering detailed mechanisms with schematic illustration. The review also covers the gap of materials synthesis and their application on polymeric textiles which could be used for EMI shielding applications. Furthermore, recent research regarding rendering EMI shielding properties at various stages of polymeric textile development is provided for readers with critical analysis. Lastly, the applications along with environmental compliance have also been presented for better understanding.

Achieving flexible and durable electromagnetic interference shielding fabric through lightweight and mechanically strong aramid fiber wrapped in highly conductive multilayer metal

Lightweight and flexible electromagnetic interference (EMI) shielding materials with excellent electrical conductivity, mechanical performances and environmental stability are urgently demanded to address EM radiation pollution in the fields of aerospace, robotics, fabric sensors and flexible antennas. Herein, an outstanding candidate material for EMI shielding of an aramid fiber (AF) core wrapped in a composite metal shell composed of amorphous Ni, crystalline Cu and Ni has been successfully manufactured through delicate architecture design and convenient preparation approach. The Ni/Cu/Ni coated AF not only retained the high load capacity and high thermal stability of the substrate, but also achieved a low resistivity of the same order of magnitude as that of metallic Cu. Even after being corroded via HCl, NaOH, NaCl solution for 48 h and treated at a high temperature of 150°C for 168 h, it still maintained good mechanical properties and electrical conductivity, demonstrating satisfactory environmental stability. The morphology and resistance of Ni/Cu/Ni coated AF after thermal shock and 500 bending cycles have no significant changes, which indicated that the bonding of Ni/Cu/Ni and AF was firm. Furthermore, the existence of AF/Ni, Ni/Cu and Cu/Ni multiple interfaces enhanced the multiple reflection and absorption of EM radiation, and final fabric showcased stronger absorption and weaker reflection of EM radiation.

A novel structural design of shielding capsule to prepare high-performance and self-healing MXene-based sponge for ultra-efficient electromagnetic interference shielding

Structural design plays an important role in the fabrication of high-performance electromagnetic interference (EMI) shielding materials, as well as determining the shielding efficiency and the corresponding shielding mechanism. Herein, a unique structure based on the shielding capsules was built in a lightweight, flexible, and self-healing EMI shielding sponge through the simple dip-coating method. In brief, the perfect MXene membranes formed and covered the pores of the melamine sponge by precisely tuning the coating parameters, connecting the porous skeletons into plenty of shielding capsules. As a result of the significantly enhanced interaction chances between electromagnetic waves and MXene membranes, the prepared composite sponge possessed a high EMI shielding effectiveness (EMI SE) of 90.49 dB in the range of X-band (8.2–12.4 GHz) with a dominant contribution of SEA as high as 93% at an extremely low loading of Ti3C2Tx (0.82 vol%). In addition, the incorporation of polyurethane (PU) sandwich endowed the materials with a self-healing function. After a cut-off and healing cycle, the healed sponge still held a high EMI SE of 72.89 dB with a shielding efficiency of 99.999995% and supported 1475 times the weight of the sample itself. Therefore, the lightweight composite sponges with such shielding capsules have excellent EMI shielding and self-healing properties, showing the great application potential in portable and wearable devices.

Freestanding "core-shell" AgNWs/metallic hybrid mesh electrodes for a highly efficient transparent electromagnetic interference shielding film.

We fabricated the freestanding "core-shell" AgNWs/ Ni mesh electrodes by employing AgNWs solution onto the freestanding Ni-mesh. The combination of AgNWs and Ni mesh resulted in higher electrical conductivity, thereby enhancing the electromagnetic interference (EMI) shielding effectiveness (SE). The hybrid freestanding electrode created highly effective transparent and flexible EMI shielding films, featuring an ultrathin thickness (3 µm), the high optical transparency of 93% at 550 nm, and a SE of 41.5 dB in the X-band, which exceeds that of 30 dB for a freestanding Ni-mesh (94%). We showed that the hybrid freestanding AgNWs/Ni-mesh film is a promising high-performance transparent and flexible EMI shielding material that satisfies the requirements for optoelectronic devices.

In-situ metallized carbon nanotubes/poly(styrene-butadiene-styrene) (CNTs/SBS) foam for electromagnetic interference shielding

The porous conductive polymer composites have received great attention owing to their superiority of being utilized in electromagnetic interference (EMI) shielding applications. Herein, lightweight and highly compressible conductive composite foam composed of poly(styrene-block-butadiene-block-styrene) (SBS) polymer matrix, carbon nanotubes (CNTs) and silver nanoparticles (Ag NPs) is fabricated by freeze-drying technology, silver precursor absorption and in-situ reduction process. Three-dimensional CNTs conductive network and partially embedded Ag NPs synergistically endow the foam with excellent mechanical, electrical and EMI shielding performance. The flexible 8Ag/4CNTs/10SBS composite foam with a low density of 0.42 g/cm3 exhibits moderate compressive strength of 169.2 kPa at strain of 50%, remarkable conductivity of 753 S/m, and prominent EMI shielding effectiveness (SE) value of around 91 dB in the electromagnetic wave frequency range of 8.2–12.5 GHz. In addition, the 4Ag/4CNTs/10SBS composite foam exhibits robust mechanical–electrical property upon 1000 compression-release cycles at strain of 50%, and its SE value increased by about 33% compared with the initial state after the cyclic compression test. These results suggest that the Ag/CNTs/SBS foams possess promising potential to be used as lightweight, flexible, and high-performance EMI shielding materials in modern electronic devices.

Fabrication of highly flexible electromagnetic interference shielding polyimide carbon black composite using hot-pressing method

Traditionally, electromagnetic interference (EMI) shielding material has been occupied by metallic materials due to its high electric conductivity and EMI shielding effect. However, with rising demands from technology development for light-weight, highly durable, and easily moldable materials, metallic materials are gradually being substituted by polymer composite materials. Still, there are limitations on polymer composite as EMI shields: High ratio of fillers in composite achieves excellent EMI shielding effect but it severely compromises its mechanical behaviors. In many studies, they have failed to fabricate the high-ratio filler films with good mechanical durability, but here the initially fragile high-ratio film has been transformed to a flexible film by a very simple method: Hot-pressing. This approach not only solved the problems mentioned above but further provided a possible breakthrough point for composite study by solving threshold of the maximum loading of the fillers in polymer matrix. The stiff composite of polyimide sponge with exceeding carbon black loading became a highly flexible EMI SE film with doubled tensile strength and enhanced EMI SE. As a result, a new way of fabricating flexible EMI shielding polymer composite is demonstrated with great potential applications in aerospace and wireless communications.

Effect of ambient plasma treatment on single-walled carbon nanotubes-based epoxy/fabrics for improving fracture toughness and electromagnetic shielding effectiveness

The development of flexible, lightweight, thin, and high-performance electromagnetic interference (EMI) shielding materials is a key challenge for dealing with the issue of increasing susceptibility in modern devices. Recently, agglomeration of carbon nanotubes (CNT) is a critical issue in CNT-based multi-scale composites used as flexible and lightweight EMI material. Herein, a ambient plasma-treatment is applied to increase the interfacial adhesion between single-walled carbon nanotubes (SWNTs) and the epoxy matrix, with control of dispersibility via an increase in the surface free energy and polar components. In spite of a low content of SWNTs, the highly dispersed conductive network thereof provides the prepared multi-scale composites with good conductivity and a high EMI shielding effectiveness (SE) of ~45.2 dB at a thickness of 0.6 mm, along with favorable flexibility and a remarkable fracture toughness (KIC) of ~36.0 MPa.m1/2.

Ultrathin, Strong, and Highly Flexible Ti3C2Tx MXene/Bacterial Cellulose Composite Films for High-Performance Electromagnetic Interference Shielding

The fabrication of ultrathin films that are electrically conductive and mechanically strong for electromagnetic interference (EMI) shielding applications is challenging. Herein, ultrathin, strong, and highly flexible Ti3C2Tx MXene/bacterial cellulose (BC) composite films are fabricated by a scalable in situ biosynthesis method. The Ti3C2Tx MXene nanosheets are uniformly dispersed in the three-dimensional BC network to form a mechanically entangled structure that endows the MXene/BC composite films with excellent mechanical properties (tensile strength of 297.5 MPa at 25.7 wt % Ti3C2Tx) and flexibility. Importantly, a 4 μm thick Ti3C2Tx/BC composite film with 76.9 wt % Ti3C2Tx content demonstrates a specific EMI shielding efficiency of 29141 dB cm2 g-1, which surpasses those of most previously reported MXene-based polymer composites with similar MXene contents and carbon-based polymer composites. Our findings show that the facile, environmentally friendly, and scalable fabrication method is a promising strategy for producing ultrathin, strong, and highly flexible EMI shielding materials such as the freestanding Ti3C2Tx/BC composite films for efficient EMI shielding to address EMI problems of a fast-developing modern society.

Transparent, Flexible, and Stable Polyethersulfone/Copper‐Nanowires/Polyethylene Terephthalate Sandwich‐Structured Films for High‐Performance Electromagnetic Interference Shielding

Transparent and flexible electromagnetic interference (EMI) shielding materials are highly desirable in wearable electronic devices and optical windows of aircrafts. Herein, transparent and flexible EMI shielding films are prepared by the use of Cu nanowires (Cu NWs). The films have a sandwiched structure composed of polyethersulfone (PES), Cu NW network, and polyethylene terephthalate (PET). The coating of PES strengthens the Cu NW contact, protects Cu NWs from the oxidation, and reduces the surface average roughness. The PES/Cu NWs/PET sandwich‐structured films show an EMI shielding effectiveness (SE) of 22 dB with an optical transmittance of 73%, and an even higher EMI SE of 30 dB in the entire X band with the optical transmittance of 67%. The PES/Cu NWs/PET sandwich‐structured films also exhibit superior flexibility, very good chemical stability in basic, acidic, and strong oxidizing solutions, as well as long‐term stability in ambient condition. This PES/Cu NWs/PET sandwich‐structured films are a promising transparent flexible EMI shielding material in wearable electronics and optical windows of aircrafts.

Fabrication of Cellulose Nanofiber/Reduced Graphene Oxide/Nitrile Rubber Flexible Films Using Pickering Emulsion Technology for Electromagnetic Interference Shielding and Piezoresistive Sensor

AbstractWith the rapid development of flexible electronics, the demand for flexible electromagnetic interference (EMI) shielding materials is increasing. This study develops a new green and effective strategy, consisting of graphene oxide (GO) and cellulose nanofibrils (CNF) co‐stabilized Pickering emulsion combined with hot‐pressing technology, to prepare flexible and conductive nitrile rubber (NBR) composite films. The composite films consist of a 3D network conductive skeleton structure of reduced GO (RGO) and an isolated NBR structure. This specific design results in a maximum high conductivity of 99 S m−1, which is higher by an order of magnitude compared with that of the composites obtained using the traditional solution blending method, and a stable EMI shielding effectiveness of 25.81 dB in the X band. The introduction of the flexible NBR results in the excellent flexibility and structural strength of the composite film, and exhibits a decrease of 2.51% in the EMI shielding efficacy after 5000 cycles. As a piezoresistive sensor for wearable devices, the CNF‐RGO/NBR flexible film can hold precise current signals and respond to finger motion. The findings of this study can provide new insights for the design of conductive and flexible composites as wearable and portable medical equipment and electronic devices.

Flexible 3D porous graphene film decorated with nickel nanoparticles for absorption-dominated electromagnetic interference shielding

Electromagnetic interference (EMI) shielding materials are vital for aerospace, military and portable wearable electronic equipment. Developing a high performance absorption-dominated EMI shielding materials with flexibility and lightness remains a challenge. Herein, we report an EMI shielding flexible thin-film composed of a 3D laser induced graphene (LIG) on polyimide substrate and magnetic nickel nanoparticles (Ni NPs) decorated in the porous LIG network. The 3D pore structure and interconnected conductive network ​​of LIG can cause the dielectric loss and multiple internal reflection dissipation of incident electromagnetic waves. Combined with the magnetic loss effect of Ni NPs, the composite thin-film exhibits ultra-efficient absorption-dominated EMI shielding performance. The EMI shielding effectiveness (SE) of a single layer optimized composite thin-film is 55 dB in the X-band (8.2–12.4 GHz) with absorption rate of 82%. The composite thin-film also possesses high flexibility with 89% EMI SE retention after 500 bendings. Furthermore, double layered composite film with thickness of only 0.327 mm can be easily prepared on both side of the polyimide substrate, exhibiting EMI SE as high as 79 dB with the absorption rate of 86%, which is superior than most of carbon- and Ni-based EMI shielding materials. Our findings may pave the way for designing high performance flexible absorption-dominated EMI shielding materials.

Enhanced electromagnetic-interference shielding effectiveness and mechanical strength of Co-Ni coated aramid-carbon blended fabric

An efficient method was proposed to prepare high-performance conductive Aramid-Carbon Blend Fabrics (ACBF) with cobalt–nickel (Co-Ni) alloy coatings, which is conducive to industrial production. The grid-like substrate composed of aramid and carbon fibers was innovatively used in flexible Electromagnetic Interference (EMI) shielding materials. The natural network structure is advantageous to the uniform deposition of metal particles to the establishment of conductive pathways subsequently in order to improve conductivity. The induction of a synergistic effect from Electromagnetic (EM) wave-reflection and EM wave-absorption through the whole carbon-Co-Ni-ternary system notably enhanced the EMI Shielding Effectiveness (SE) value to an average of 42.57 dB in the range of 30–6000 MHz. On the other hand, together with the inherent toughness of the alloy coatings, the tensile strength of the aramid fibers used for bulletproof made a significant contribution to the desired mechanical properties. The light weight of the resultant composite made it applicable to aerospace vehicles simultaneously. X-ray Photoelectron Spectroscopy (XPS) was conducted to investigate the variations of elements and groups on the sample surface in pre-treating process. The elemental components and surface morphologies of fabric samples during different stages of the process were investigated by Scanning Electron Microscope (SEM) and Energy Dispersive spectrometer (EDX) measurements. X-Ray Diffraction (XRD) results indicated that the obtained Co-Ni alloy coating had a combined Hexagonal Closed-Packed (HCP) and Faced-Centered Cubic (FCC) crystalline phase. The relatively high corrosion resistance demonstrated in different acid and alkaline conditions was instrumental in more complex environments as well.

High-Performance and Reliable Silver Nanotube Networks for Efficient and Large-Scale Transparent Electromagnetic Interference Shielding.

The development of flexible and transparent electromagnetic interference (EMI) shielding materials with excellent comprehensive properties is urgently demanded as visual windows and display devices in aeronautic, industry, medical, and research facilities. However, the method of how to obtain highly efficient and reliable transparent EMI shielding devices is still facing lots of obstacles. Here, a high-performance silver nanotube (AgNT) network with stable and integrated interconnects is prepared by physical depositing technology, based on a uniform and large-scale nanofiber skeleton. This unique structure enables the AgNT network to achieve one order higher conductivity (∼1.0 Ω/sq at >90% transmittance) than previous research studies and keeps <10% variation with random deformations (>5000 times). Moreover, the manufactured AgNT shielding film with a thickness of less than 1 mm can be easily transferred to arbitrary surfaces as a transparent and flexible EMI shielding film at commercial ∼35 dB EMI shielding effectiveness, with large-scale, low-cost, and simple preparation processes. These excellent properties endow the AgNT shielding film to achieve great potential for future flexible and transparent scenarios.

Transparent Electromagnetic Shielding Film Utilizing Imprinting-Based Micro Patterning Technology.

Utilization of methods involving component integration has accelerated, owing to the growth of the smart mobile industry. However, this integration leads to interference issues between the components, thereby elucidating the importance of the electromagnetic interference (EMI) shielding technology to solve such issues. EMI shielding technology has been previously implemented via the reflection or absorption of electromagnetic waves by using conductive materials. Nevertheless, to tackle the recent changes in the industry, a transparent and flexible EMI shielding technology is necessitated. In this study, a transparent and flexible EMI shielding material was fabricated by filling a conductive binder in a film comprising an intaglio pattern; this was achieved by using the ultraviolet (UV) imprinting technology to realize mass production. Subsequently, changes in the aperture ratio and shielding characteristics were analyzed according to the structure of the pattern. Based on this analysis, a square pattern was designed and a film with an intaglio pattern was developed through a UV imprinting process. Furthermore, it was confirmed that the transmittance, conductivity, and EMI shielding rate of the film were altered while changing the coating thickness of the conductive particles in the intaglio pattern. The final film prepared in this study exhibited characteristics that satisfied the required EMI shielding performance for electric and electronic applications, while achieving flexible structural stability and transparency.

Co/multi-walled carbon nanotubes/polyethylene composites for microwave absorption: Tuning the effectiveness of electromagnetic shielding by varying the components ratio

We present novel polyethylene (PE) composites for electromagnetic interference (EMI) shielding application. They are based on cobalt modified multi-walled carbon nanotubes (MWCNTs) produced via in situ polymerization of ethylene, with the Ti-Ziegler–Natta catalyst preliminarily immobilized on Co/MWCNT hybrids. The electromagnetic properties of the composites were tuned by varying the filler loading and Co:MWCNT ratio. The microstructure of the composites and electromagnetic absorption process were carefully characterized by transmission and scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, ferromagnetic resonance and vector network analysis. The electromagnetic wave absorbing properties of the nanocomposite were investigated in the 10 MHz−18 GHz frequency range revealing that the EMI absorption properties can be tuned by varying the Co:MWCNT weight ratio in the filler. Interestingly, the Co/MWCNT-PE composite with a total filler and Co loading of only 12 and 1.7 wt%, respectively, showed extremely high reflection loss (RL) of −55 dB. More importantly, an effective bandwidth of 12.8–17.8 GHz (RL below −10 dB) was achieved for a matching thickness of only 1.5 mm. The specific RL value (RL/filler loading) of the composite was superior in comparison with the previously reported nanostructured carbon materials. The highly effective absorbing properties of Co/MWCNT-PE composites are explained primarily by the unprecedented uniform filler distribution in the polyethylene as well as by the synergistic effect of MWCNTs and Co nanoparticles. This approach thus offered an effective strategy to design cost-effective, lightweight and flexible EMI shielding materials with tunable dielectric and magnetic performance.

Development and current situation of flexible and transparent EM shielding materials

The application of electromagnetic (EM) technology has greatly promoted the progress and development of society, and also brought the side effects of EM interference (EMI). In the fields of visualization windows, transparent wearable devices, and aerospace equipment, flexibility and transparency have become the performance requirements of EMI shielding materials. Materials such as metal-based materials, MXenes, carbon-based materials, and conductive polymers show the potential for flexibility and transparency and lots of cases have been developed. This article summarizes the flexible and transparent properties of mainstream EMI shielding materials, and evaluates their potential as flexible and transparent EMI shielding materials. Finally, the research progress of flexible and transparent EMI shielding materials based on different advanced technologies is summarized.

Exfoliated graphite nanoplatelet (xGnP) filled EVA/EOC blends nanocomposites for efficient microwave absorption in the S-band (2–4 GHz)

Inspired by hazardous effects of electromagnetic waves on human health related to increasing exposure to electronic devices in day-to-day life we have developed a low cost, light weight and flexible EMI shielding material based on exfoliated graphite nanoplatelets (xGnP) filled ethylene vinyl acetate (EVA)/Ethylene-octene copolymer (EOC) blend composite by melt mixing method. X-ray diffraction revel that inclusion of xGnP affect the crystallinity of EVA/EOC blend which has also been seconded by differential scanning calorimetry (DSC) analysis. Electromagnetic interference (EMI) shielding effectiveness of the nanocomposites and electromagnetic properties were conducted over microwave frequency range of 1.5–8 GHz. It has been observed that with inclusion of xGnP into EVA/EOC matrix there is significantly improvement of EMI SE values in S- band (2–4 GHz) region and highest total EMI SE value of −67.63 dB at 30 wt% of xGnP loading was achieved mainly due to absorption mechanism. The composite exhibit ac conductivity of 455.8 S/m which is much higher than that of neat EVA/EOC blends. The dc conductivity 5.3 × 10−8 S/m was obtained for 30 wt% xGnP EVA/EOC blend. To our belief, this EVA/EOC/xGnP composite can be utilized as an efficient EMI shielding material in S-band.