Superior Electromagnetic Shielding Research Articles

FDM 3D printed MXene/Recycled carbon fibre reinforced polylactic acid composites: Interface optimization, toughening and enhanced electromagnetic shielding performance

Polylactic acid (PLA), a rapidly emerging bio-based plastic, faces challenges in reinforcement due to its weak mechanical properties and poor interface adhesion with carbon fibre surfaces. This study introduces an MXene/recycled carbon fibre (rCF) reinforced PLA 3D printing material, prepared through electrostatic self-assembly of MXene and recycled carbon fibre. MXene addition significantly enhances the fibre-substrate interface bonding in fibre-reinforced PLA filaments. This results in the printed parts displaying enhanced toughness, the flexural strength achieved of 105.45 MPa, modules of 5.98Gpa, and notched impact strength of 7.12 kJ/m2, realizing 15.6 %, 112.1 %, and 31.8 % improvements, respectively in comparison to pure PLA. Additionally, the modified PLA demonstrates absorption-dominated superior electromagnetic shielding performance. This research offers a viable approach for enhancing recycled carbon fibre-reinforced thermoplastic PLA and insights into designing sustainable, structurally, and functionally integrated composites.

Silver-Coated Waste Rubber Micro-Particles with Low Density, High Stability, and Excellent Electromagnetic Shielding Ability: Design, Preparation, and Characterization

Introduction: The electromagnetic radiation caused by the increasing application of electronic devices is associated with environmental hazards and health risks. background: The electromagnetic radiation caused by the increasing application of electronic devices is associated with environmental hazards and health risks. With the rapid development of science and technology, it is urgent to reduce electromagnetic interference by introducing effective electromagnetic shielding materials. Furthermore, novel electromagnetic shielding materials with increasing stability and decreasing density have become the focus of the current researches. Method: With the rapid development of science and technology, it is urgent to reduce electromagnetic interference by introducing effective electromagnetic shielding materials. Furthermore, novel electromagnetic shielding materials with increasing stability and decreasing density have become the focus of the current research. Herein, silver (Ag) coated rubber (AR) micro-particles (MPs) were prepared by coating Ag nanoparticles (NPs) onto waste AR MPs. objective: Fabrication of Silver (Ag) coated rubber (AR) micro-particles (MPs). Result: The AR MPs not only exhibited superior electromagnetic shielding performance with the electromagnetic interference (EMI) shielding effectiveness (SE) value of 6.1 dB at 5.8 GHz, but also possessed excellent long-time stability (240 h) in high-temperature (85 °C) and high humidity (85% RH) environment. Due to the low density (0.66 g/cm3) of AR-3 MPs, its practical application in lightweight and highly integrated electronic devices is guaranteed. Conclusion: The developed AR MPs have exhibited broad application prospects in the electromagnetic interference (EMI) shielding field due to the good EMI shielding performance, high stability and low density.

Lightweight and high-strength polyarylene ether nitrile-based composites for efficient electromagnetic interference shielding

Abstract The proliferation of electronic devices and the widespread adoption of microwave-based technologies have resulted in a notable rise in electromagnetic radiation pollution. In present work, a novel flexible lightweight polyarylene ether nitrile (PEN)-based composite for efficient electromagnetic interference (EMI) shielding was prepared by introducing dual-loss hybrid material (PKMWCNT@Fe3O4) into PEN via non-solvent induce phase separation method and assembling it layer-by-layer with carbon fiber (CF) fabric. The porous morphology of the PEN layer, the electrical conductivity of the CF fabric, and the dual-loss property of the filler enable the material to reflect and absorb electromagnetic waves multiple times, resulting in superior electromagnetic shielding performance. With the addition of PKMWCNT@Fe3O4 at a mass fraction of 50%, the EMI SE T and specific shielding effectiveness SSE/t can reach up to 47.08 dB and 617 dB cm2/g, respectively, indicating absorption dominated shielding mechanism. Furthermore, the material exhibits a lightweight nature with a density of 0.55 g/cm3, and excellent mechanical properties, including a tensile strength of 43.98 MPa and elongation at break of 43.32%. This work presents a new approach to prepare high-performance composites that are both lightweight and resistant to secondary contamination by electromagnetic waves.

A waste textiles-based multilayer composite fabric with superior electromagnetic shielding, infrared stealth and flame retardance for military applications

The challenge of developing multifunctional military tent fabrics with low-cost, stable electromagnetic shielding and infrared stealth in complicated environments is enormous. Herein, a novel aluminium-flammability carbonized waste cotton-carbon felt (A-FCWCF) composite fabric consisting of hydrophobic flame-retardant fabric, carbonized waste cotton felt and carbon fiber felt was prepared via a simple yet low-cost stitching process. The resulting composite fabric was extensively investigated for its stability and applicability in a complicated environment. Due to the significant conductivity and impedance mismatches, the A-FCWCF composite fabric displayed exceptional EMI-shielding properties, plus an X-band EMI rating of 82.63 dB. Moreover, the A-FCWCF composite fabric presented excellent infrared stealth performance at room and extremely cold outdoor temperatures, owing to its high porosity and low emissivity. The functional finishing on the A-FCWCF composite fabric also made it stable flame retardate and hydrophobic. Furthermore, the EMI-shielding and infrared stealth performances of A-FCWCF composite fabric were almost unaffected even if subjected to environmental stability, mechanical properties and weather resistance tests, making it a promising candidate for tough natural environments. Overall, this low-cost and simple preparation strategy of multi-layer stitched multifunctional fabric can revolutionize the production of military materials, improving functionality even in the most complex environments.

High-Adhesion Ag Film with Enhanced Electromagnetic Shielding Performance via Post-Treatment of a Polydopamine Adhesive Layer.

Low adhesion limits the application of the conformal metal coating based on metal-organic complexing deposition (MOD) ink in electromagnetic interference shielding with an ultrathin thickness and excellent electromagnetic shielding performance. Here, the mussel-inspired polydopamine (PDA) coating with double-sided adhesive characteristic was used to modify the substrate surface, and a high-adhesion silver film was prepared by spin-coating MOD ink on the PDA-modified substrate. The surface chemical bond of the deposited PDA coating was found to change with the exposure time under air in this work, and three post-treatment methods were carried out on the PDA coatings, including exposure to air for 1 min, exposure to air for a day, and oven heat treatment. The influences of such three post-treatment methods of PDA coating on the structure of the substrate surface, the silver film adhesion property, the electrical property, and the electromagnetic shielding property were studied. The adhesion of the silver film was effectively enhanced up to 20.45 MPa by controlling the post-treatment method of the PDA coating. The PDA coating was found to increase the sheet resistance of the silver film and to absorb electromagnetic waves. By optimizing the deposition time and the post-treatment condition of the PDA coating, superior electromagnetic shielding effectiveness up to 51.18 dB was obtained with a thin silver film of 0.42 μm. The introduction of the PDA coating improves the applicability of the MOD silver ink in the field of conformal electromagnetic shielding.

A highly strong PEDOT modified wood towards efficient electromagnetic interference shielding

In the development of the modern electronics industry, the high mechanical performance, the green, and high-performance electromagnetic interference (EMI) shielding materials need to urgently be developed. Herein, polythiophene/Wood (PEDOT/wood) was fabricated through in situ polymerizing thiophene in the delignified paulownia wood. The results indicated that PEDOT were evenly distributed on the carbohydrates framework of the wood, endowing the composite with a highly electrical conductivity of 112.8 S m−1 and a superior electromagnetic shielding effectiveness of 46.2 dB at 2 mm thickness. The normalized SE (EMI SE/thickness) of the composite calculated as 213 dB/cm. Meanwhile, a high compressive strength and tensile strength of the prepared PEDOT/wood composite were tested as 50.9 MPa and 67.8 MPa, respectively. Such a high conductivity, strong mechanical properties and renewable PEDOT/wood suggests it as a potential candidate for the application in electromagnetic interference shielding and paves a new way for the biomass-based electromagnetic shielding materials.

Efficient recycling of carbon fiber from carbon fiber reinforced composite and reuse as high performance electromagnetic shielding materials with superior mechanical strength

Carbon fiber reinforced boron phenolic resin composite (CF/BPR) is widely used. However, it is hard to decompose its waste for highly cross-linked networks. Herein, a solvothermal decomposition route was proposed to decompose CF/BPR and recycle carbon fibers. Decomposition ratio of resin (Dr) reached 99.78%. Possible decomposition mechanism was proposed based on characterizations of decomposition products. Composite was decomposed for synergistic effects of physical swelling, mechanical impact and chemical decomposition. Surface morphology and microstructure characterization of recycled carbon fibers (RCFs) confirmed that resin was highly removed while no significant harm was caused to RCFs. It was found that RCFs reinforced boron phenolic resin composite (RCFs/BPR) had superior punch type shear strength due to improved wettability and interfaces. Moreover, RCFs/BPR exhibited superior electromagnetic shielding performance in X-band frequency for improved conductive network. This work presents a facile and efficient pathway for decomposing composite waste and reuse as high performance electromagnetic shielding materials.

Superhydrophobic, mechanically robust and self-cleaning MXene/wood composite for high-performance electromagnetic interference shielding

Designing multifunctional characteristic of MXene-based materials with high efficient electromagnetic interference (EMI) shielding is crucial for alleviating radiation pollution yet challenging. Nevertheless, the hydrophilicity of MXene-based materials may result in the reduction of electromagnetic shielding performance in humid environments. In this study, superhydrophobic, mechanically robust, and EMI shielding-effective composite of MXene/Wood (WP-MXene/Delignified wood) is fabricated via a facile and effective thermocompression combined with dip-coating approach. The MXene nanosheets are uniformly distributed in the hierarchical porous structure, which endows the WP-MXene/Delignified wood with remarkable mechanical performance with a tensile strength of approximately 111.4 MPa, and excellent electromagnetic shielding of 43.4 dB. In addition, such composite also possesses prominent waterproof property with a contact angle of 155.1°. The high-strength, superhydrophobic MXene-based wood with superior electromagnetic shielding performance holds tremendous application prospects for EMI shielding and energy-efficient buildings.

Heterogeneous asymmetric double-layer composite with ultra-low reflection for electromagnetic shielding

In this work, a heterogeneous asymmetric double-layer composite (HADC) consisting of an absorbing layer Fe3O4@reduced graphene oxide (rGO)/waterborne polyurethane (WPU) and a reflecting layer Ni-Co-P@FC (Ni-Co-P coated filter cotton (FC)/PANI@PDMS (polyaniline (PANI) mixed in polydimethylsiloxane (PDMS)) was designed and prepared using a simple chemical plating method and stirred foaming process. In which, the upper Fe3O4@rGO/WPU foam utilizes the combined effects of the porous internal structure and Fe3O4@rGO to achieve superior impedance matching and electromagnetic waves (EMW) absorption performance, while the Ni-Co-P dense conductive network formed by chemical plating process within the bottom layer ensures superior electromagnetic shielding effectiveness (EMI SE). The advantage of heterogeneous asymmetric structure combined with the reasonable distribution of electromagnetic two-component fillers and under the effects of multiple electromagnetic loss mechanisms, the composite structure perfectly overcomes the contradiction between efficient shielding and high absorption. Ultimately, the HADC exhibits a high EMI SE of 36.6 dB and absorption coefficients (A) value of 0.94, showing ultra-low reflection efficiency, which is better than most current shielding materials moreover, the preparation process is simple, with the characteristics of low cost and environmentally friendly. Therefore, this work provides a simple and feasible new idea for the preparation of lightweight, efficient and ultra-low reflection EMI shielding composite structures, which broadens the application of porous structures in the field of electromagnetic shielding.

Direct current magnetron sputtered Ni3Al thin films with electron transport behaviour for superior electromagnetic shielding

Direct current magnetron sputtered Ni3Al thin films with electron transport behaviour for superior electromagnetic shielding

Asymmetric conductive structure design for stabilized composites with absorption dominated ultra-efficient electromagnetic interference shielding performance

Structurally asymmetric melamine foam (MF)/Polyaniline (Pani)/Fe3O4@reduced graphene oxide (rGO)/Ag-plated aramid paper (AgP)/Polydimethylsiloxane (PDMS) stabilized composites were successfully designed with controlled distribution of the conductive network to accomplish harmonization of electromagnetic absorption and shielding. Wherein, the upper MF/Pani/Fe3O4@rGO/PDMS foam combines in-situ polymerization and dip coating methods utilizing the synergistic effect of conductive Pani and Fe3O4@rGO to achieve superior impedance matching and absorption performance, while the dense conductive network formed in the bottom AgP by electroless plating technique ensures superior electromagnetic shielding effectiveness (EMI SE). With the rational arrangement of the absorptive and conductive shielding layers, MF/Pani/Fe3O4@rGO/AgP/PDMS composites demonstrate of 70 dB and extremely high absorption coefficient (A) of 0.86 at X-band. Notably, benefiting from the asymmetric structural design and PDMS wrapping, the composites possess superior thermal stability, mechanical strength and stable EMI SE. This valid work delivers a useful concept for the rational regulation of conductive networks in shielding composites, improving the applicability in practical environments.

Shorted Micro‐Waveguide Array for High Optical Transparency and Superior Electromagnetic Shielding in Ultra‐Wideband Frequency Spectrum

AbstractWhile functional materials with both light transmitting and electromagnetic shielding are highly desirable and have made rapid advancements, only very few of them meet the stringent electromagnetic interference (EMI) shielding criteria for optoelectronic systems. Achieving high optical transparency and superior EMI shielding in a broad frequency spectrum is a remaining challenge in both academic and industrial areas. Herein, a design strategy of shorted micro‐waveguides (SMWs) array to decouple the light transmission and EMI shielding is proposed and experimentally demonstrated. The array of SMWs, consisting of cutoff metallic micro‐waveguides and shorting indium tin oxide (ITO) continuous conductive film, exhibits high optical transmittance of 90.4% and superior EMI shielding effectiveness of 60.8 dB on average over ultra‐wide frequency spectrum (0.2–1.3 GHz & 1.7–18 GHz). Compared to previously reported works, an improvement of 17 dB in average shielding effectiveness is achieved under the same level of light transmission, and the shielding frequency spectrum is significantly expanded. The working principle is explained in depth and factors influencing the performance are investigated for design optimization. These outstanding properties enable the transparent shielding material based on SMWs to excel in future applications of EMI shielding for optoelectronic systems.

Effect of Substitutional Oxygen on Properties of Ti3 C2 Tx MXene Produced Using Recycled TiO2 Source.

MXenes are an emerging class of 2D materials with unique properties including metallic conductivity, mechanical flexibility, and surface tunability, which ensure their utility for diverse applications. However, the synthesis of MXenes with high crystallinity and atomic stoichiometry in a low-cost process is still challenging because of the difficulty in controlling the oxygen substitute in the precursors and final products of MXenes, which limits their academic understanding and practical applications. Here, a novel cost-effective method is reported to synthesize a highly crystalline and stoichiometric Ti3 C2 Tx MXene with minimum substitutional oxygen impurities by controlling the amount of excess carbon and time of high-energy milling in carbothermal reduction of recycled TiO2 source. The highest used content (2wt%) of excess-carbon yields TiC with the highest carbon content and minimal oxygen substitutes, which leads to the Ti3 AlC2 MAX phase with improved crystallinity and atomic stoichiometry, and finally Ti3 C2 Tx MXene with the highest electrical conductivity (11738 S cm-1 ) and superior electromagnetic shielding effectiveness. Additionally, the effects of carbon content and substitutional oxygen on the physical properties of TiC and Ti3 AlC2 are elucidated by density-functional-theory calculations. This inexpensive TiO2 -based method of synthesizing high-quality Ti3 C2 Tx MXene can facilitate large-scale production and thus accelerate global research on MXenes.

Interlayer decoration of expanded graphite by polyimide resins for preparing highly thermally conductive composites with superior electromagnetic shielding performance

Polymer-based conductive composites are promising thermal management and electromagnetic interference (EMI) shielding materials that are highly desired in modern integrated electronics and fifth-generation mobile communication technology, yet remain extremely challenging to fabricate (e. g., homogeneous dispersion of nanofillers, construction of continuous conductive network and formation of strong interfacial interaction, etc). Herein, we report a strategy to boost the thermal conduction and EMI shielding properties of polyimide (PI)-based composites by constructing large-size aligned graphite sheets inside PI matrix. The main steps includes initial self-assembly of PI microspheres into the interlayer space of polydopamine-modified expanded graphite (EG-PDA), subsequent decoration of interlayer space of EG-PDA by PI resins via microspheres melting and permeating, and the final hot pressing densification. In this way, the large-sized graphite sheets consisted of lateral van-der-Waals (vdW)-bonded and oriented graphite nanosheets within the composites can form consecutively conductive pathways, which together with the enhanced interface affinity between PI and EG-PDA via hydrogen-bonding synergistically improve the in-plane thermal conductivity to an optimum value of 65.6 W m−1 K−1 with outstanding EMI shielding effectiveness of 101 dB at filler loading of 60 wt%. In addition, the high thermal conductivity and EMI shielding performance can be retained after being subjected to combustion or chemically corrosive environments, and in repeated processing, revealing broad prospects in the fields of next-generation electronic devices.

Multifunctional fireproof electromagnetic shielding polyurethane films with thermal management performance

A multifunctional polyurethane film (PU) with superior electromagnetic shielding performance, joule heating performance, thermal conductivity and flame retardancy has been carefully designed. The ammonium polyphosphate (APP) wrapped with conductive MXene (MAPP) is prepared by microencapsulation technology and added in PU solution for enhancing the electric conductivity of PU/graphite fiber (GF) film. The three-dimensional (3D) conductive network composed of GF and MAPP promotes electron transmission efficiency and electromagnetic (EM) wave dissipation through multiple absorbtion and reflection. Compared with the PU/GF film, the electric conductivity and thermal conductivity of PU/GF/MAPP film enhanced by 57.7% and 59.3%, respectively. What’s more, the PU composite film shows excellent mechanical properties, joule heating performance and high fire safety performance. Therefore, the prepared multifunctional PU film demonstrates excellent performance, and has broad application prospects in EMI shielding and thermal management of advanced microelectronic systems.

Superior Electromagnetic Shielding and Mechanical Buffering Achieved by Alternating Conductive and Porous Supramolecular Networks

The development of electromagnetic interference (EMI) shielding materials with excellent EMI shielding effectiveness (SE), and superior mechanical performance is of great importance in daily life and in the military, where they are used for intelligent transportation systems and ammunition. Generally, shielding performances can be realized via reflection loss and absorption loss. However, it is still a challenge to enhance these two kinds of electromagnetic wave loss in the same material at the same time to achieve ideal shielding performance. Herein, a flexible Ag NDs/CNT@PC/Ni‐9 film composed of five conductive layers and four porous layers is prepared by alternating Ag NDs/CNT layers and PC/Ni layers through self‐assembly. The obtained film with a thickness of 890 μm exhibits a remarkable SE performance of 138 dB in the X‐band. Additionally, with a series of continuous volcanic mechanical impacts (>10 000 g), the maximum instantaneous acceleration is decreased by 30.02% due to the buffering of the film, which constitutes a much‐improved energy absorption cushion relative to that of traditional buffering materials, such as foam metal and rubber. A material integrated with strong EMI shielding and high mechanical shock resistance is designed, which provides an effective strategy for the development of functional materials for extreme environments.

Thermally Conductive Poly(lactic acid) Composites with Superior Electromagnetic Shielding Performances via 3D Printing Technology

Thermally Conductive Poly(lactic acid) Composites with Superior Electromagnetic Shielding Performances via 3D Printing Technology

Micro-diamond assisted bidirectional tuning of thermal conductivity in multifunctional graphene nanoplatelets/nanofibrillated cellulose films

Environmentally friendly thermal interface materials (TIMs) with bidirectional high thermal conductivities have aroused considerable interests for addressing the heat dissipation issue in integrated circuits. Although graphene-based TIMs exhibit excellent in-plane thermal conductive performance, their through-plane thermal conductivity is commonly less than 3 Wm−1K−1 owing to the vast interfacial phonon scattering, significantly limiting their practical applications. In this study, a strategy aimed at building TIMs with controllable heat transfer pathways both along the in-plane and through-plane directions is proposed by incorporating micron-diamonds (MDs) in graphene nanoplatelets/nanofibrillated cellulose (GNPs/NFC) composite film via a facile and green self-assembly method. The morphology of the obtained MDs@GNPs/NFC composite film can be precisely tailored from a hierarchical structure to a 3D solid foam-like structure to tailor heat transfer paths. By adjusting the loading and particle size of MDs, a through-plane thermal conductivity of 8.85 Wm−1K−1 was achieved accompanied with a simultaneously high in-plane thermal conductivity of 32.01 Wm−1K−1. The excellent bidirectional thermal conductive performance is integrated with high-efficiency Joule heating capability, outstanding nonflammability, as well as superior electromagnetic shielding performance, showing a promising future in advanced electronic devices.

Flexible, stretchable and electrically conductive PDMS decorated with polypyrrole/manganese-iron oxide nanocomposite as a multifunctional material for high performance EMI shielding applications

Rapid growth in portable and wearable electronics requires high performance electromagnetic shielding materials that are lightweight, flexible, stretchable and electrically conductive to counter the problems of increasing electromagnetic pollutions. Absorption dominant microwave wrap-on shielding materials are in great demand for mitigating the effect of electromagnetic interference on devices and the environment. In this work we report preparation of a multifunctional composite that effectively combines the outstanding EMI shielding, electrical conductivity mechanical flexibility and magnetic properties of hybrid polymer nanocomposite systems for wearable electronics. Highly conductive Polypyrrole (PPy)/Manganese-Iron oxide (MnFe2O4) nanocomposites treated with para toluene sulphonic acid (PTSA) were incorporated into polydimethylsiloxane (PDMS) matrix to obtain a multifunctional hybrid structure. The incorporation of PTSA treated PPy- MnFe2O4 nanoparticles forms excellent conductive network and improves the electrical and magnetic properties of the composites. The PDMS based nanocomposite exhibit superior conductivity of 24.03 S/cm with robust mechanical properties such as Young’s modulus (0.93 MPa) and tensile strength (2.62 MPa). Due to improved conductivity and magnetic attributes this PDMS based nanocomposite with 0.5 mm thickness shows absorption dominated superior electromagnetic shielding performance (EMI-SE of −21 dB corresponds to 99.21% of shielding efficiency) in X-band microwave frequencies. Further, these nanocomposite shields exhibit excellent stability in conductivity and EMI-SE values under mechanical stretching and bending. Apart from being an excellent shielding material, this PDMS based nanocomposite serves as a superior strain sensor, indicates multifunctional dimensions of this material. Owing to the features such as light weight, flexibility, stretchability, high conductivity, excellent EMI-SE as and superior strain sensing performance, these composites can be used in flexible and foldable devices as smart wrap-on shield.

A review on electromagnetic shielding magnesium alloys

Electromagnetic waves generated by electronic equipment are widely present in all living and working spaces because of the rapid development of electronic products and frequent use of digital systems. Electromagnetic shielding is an effective method of protection against these waves. Therefore, the demand for materials with high electromagnetic shielding properties has remarkably increased. Magnesium (Mg) alloys, as potential electromagnetic shielding materials, have sparked great interest worldwide. This review highlights the effects of grain size, texture, alloying elements and second phase on the shielding properties of Mg alloys. Recent progress on the shielding properties of Mg–Zn, Mg–Al, Mg–RE and other new shielding Mg alloys is then summarised, and the successful design of Mg alloys with superior electromagnetic shielding properties, such as Mg–Zn–Y–Ce–Zr, Mg–Sn–Zn–Ca–Ce, Mg–Gd–Y–Zn–Zr and Mg-based composite materials, is described. Finally, this review provides insights into the future development and applications of Mg alloys with superior shielding properties.