Electromagnetic Shielding Fabric Research Articles

Capillarity-assisted assembly of composite fibers to enable highly conductive fabrics for electromagnetic interference shielding

Poor adhesion between silver nanomaterials and substrates seriously restricts the development of electronic composite devices. In this work, flexible and conductive silver nanowires/fibroin/degummed silk (AgNWs/fibroin/dSF) composite fibers with high adhesion and conductivity via capillarity-assisted assembly for electromagnetic interference (EMI) shielding are designed and fabricated by a facile and scalable all-solution dip-coating method. The nanocomposite fiber possesses high conductivity with a resistance of 8.8 Ω/cm at a low AgNWs/fibroin loading of 19.3 wt%. The assistance of the capillary force in the fiber highly increases the mass of deposited AgNWs. Furthermore, the AgNWs show high adhesion on the fibers in the tape-peel test. The enhanced deposition factors and mechanisms are detailly investigated. Moreover, the composite fibers are further woven into a soft and flexible fabric. The composite fabric shows an absorption-dominated EMI shielding performance with an efficient shielding effectiveness of 38 dB. The capillarity-assisted assembly is an attractive procedure for constructing high-conductive and uniform coatings for a wide application.

Effect of carbon nanotube fiber on shielding effectiveness of stainless-steel electromagnetic shielding fabric

PurposeStainless-steel electromagnetic shielding (EMS) fabrics are widely applied as protective materials against electromagnetic interference (EMI). However, these fabrics primarily shield electromagnetic waves through reflection, which can lead to the formation of resonance effects that severely compromise their protective capabilities and potentially cause secondary electromagnetic pollution in the external environment.Design/methodology/approachIn this paper, carbon nanotube fibers are added via spacing method to replace some stainless-steel fibers to impart absorbing properties to stainless-steel EMS fabric. The shielding effectiveness (SE) of the EMS fabrics across various polarization directions is analyzed. Additionally, a spacing arrangement for the carbon nanotube fibers is designed. The EMS fabric with carbon nanotube fibers is manufactured using a semi-automatic sample loom, and its SE is tested using a small window method test box in both vertical and horizontal polarization directions.FindingsAccording to the experimental data and electromagnetic theory analysis, it is determined that when the spacing between the carbon nanotube fibers is less than a specific distance, the SE of the stainless-steel EMS fabric significantly improves. The fabric exhibits stable absorbing properties within the tested frequency range, effectively addressing the issue of secondary damage that arises from relying solely on reflective shielding. Conversely, as the spacing between the carbon nanotube fibers exceeds this distance, the SE diminishes. Notably, the SE in the vertical polarization direction is substantially higher than that in the horizontal polarization direction at the same frequency.Originality/valueThis study provides a new path for the development of high-performance EMS fabrics with good wave-absorption characteristics and SE.

Lightweight and flexible Ag-wrapped polyimide aerogel fabrics for electromagnetic interference shielding

Lightweight, flexible and highly effective electromagnetic interference (EMI) shielding fabrics are urgent demanded to protect the human body from harmful electromagnetic radiation. However, the design of fiber microstructures for achieving high-performance EMI shielding still remains significant challenges. Herein, novel EMI shielding fabrics have been designed based on polydopamine-assisted Ag deposition on polyimide (Ag@PI) aerogel fabrics. The Ag@PI aerogel fabric integrates highly conductive Ag and leverages the three-dimensional porous structure of aerogel to facilitate multiple reflections and interface polarization of electromagnetic waves. The Ag@PI aerogel fabrics exhibit ultra-high electromagnetic interference shielding performance of 89.4 dB owing to their unique porous structure, while the Ag@PI fabric without porous structure is only 65.1 dB. The normalized specific shielding effectiveness (SSE) of the Ag@PI aerogel fabrics is up to 812.7 dB cm3 g−1, significantly exceeding that of other EMI shielding textiles reported so far.

Nanoengineering Natural Leather for Dynamic Thermal Management and Electromagnetic Interference Shielding.

Unpredictable and extreme weather conditions, along with increasing electromagnetic pollution, have resulted in a significant threat to human health and productivity, causing irreversible damage to society's well-being and economy. However, existing personal temperature management and electromagnetic protection materials lack adaptability to dynamic environmental changes. To address this, a unique asymmetric bilayer leather/a-MWCNTs/CA fabric isdeveloped by vacuum-infiltrating interconnected a-MWCNTs networks into natural leather's microfiber backbone and spraying porous acetic acid (CA) on the reverse side. Such fabric achieves simultaneous passive radiation cooling, heating, and anti-electromagnetic interference functions without external energy input. The fabric's cooling layer has high solar reflectance (92.0%) and high infrared emissivity (90.2%), providing an average subambient radiation cooling effect of 10 °C, while the heating layer has high solar absorption (98.0%), enabling excellent passive radiative heating and effective compensation for warming via Joule heating. Additionally, the fabric's 3D conductive a-MWCNTs network provides electromagnetic interference shielding effectiveness of 35.0dB mainly through electromagnetic wave absorption. This multimode electromagnetic shielding fabric can switch between cooling and heating modes to adapt to dynamic cooling and heating scenarios, providing a new avenue for sustainable temperature management and electromagnetic protection applications.

Shielding Performance of Electromagnetic Shielding Fabric Implanted with “Split-Ring Resonator”

The electromagnetic shielding (EMS) fabric is an important electromagnetic protection product, which is widely applied in various fields. The improvement of its shielding effectiveness (SE) has always been the focus of research. This article proposes to implant a metamaterial structure of a "split-ring resonator (SRR)" in the EMS fabrics, so that the fabric not only maintains the porous and lightweight characteristics, but also obtains the SE improvement. With the help of the invisible embroidery technology, stainless-steel filaments were used to implant hexagonal SRRs inside the fabric. The effectiveness and influencing factors of the SRR implantation were described by testing the SE of the fabric and analyzing the experimental results. It was concluded that the SRR implantation inside the fabric can effectively improve the SE of the fabric. For the stainless-steel EMS fabric, the increase amplitude of the SE reached between 6 dB and 15 dB in most frequency bands. The overall SE of the fabric showed a decrease trend with the reduction of the outer diameter of the SRR. The decrease trend was sometimes fast and sometimes slow. The decreasing amplitudes were different in various frequency ranges. The number of embroidery threads had a certain effect on the SE of the fabric. When other parameters remained unchanged, the increase of the diameter of the embroidery thread resulted in the increase of the SE of the fabric. However, the overall improvement was not significant. Finally, this article also points out that other influencing factors of the SRR need to be explored, and the failure phenomenon may occur under certain situations. The proposed method has the advantages of the simple process, convenient design, no pore formation, SE improvement retaining the original porous characteristics of the fabric. This paper provides a new idea for the design, production, and development of new EMS fabrics.

Superhydrophobic and Durable Silver-Coated Fabrics for Efficient Electromagnetic Interference Shielding

Superhydrophobic surfaces present promising potential for improving the mechanical and chemical durability of electromagnetic interference (EMI) shielding materials. However, integrating superhydrophobicity and EMI shielding is still a challenge due to the complex structural design. Herein, superhydrophobic and highly durable fabrics with excellent EMI shielding effectiveness were fabricated. First, the meta-aramid nonwoven fabrics were functionalized by a polydopamine layer. Then, with the assistance of the metal-binding ability of polydopamine, silver nanoparticles were immobilized on the fiber surface by electroless plating. Finally, after the introduction of fluorine-containing agents via a facile dipping method, a superhydrophobic surface was successfully obtained. The as-prepared fabrics showed excellent EMI shielding effectiveness of 111 dB due to superior electrical conductivity (234 S/cm). Moreover, thanks to the low surface energy of fluorine-containing molecules as well as the micro-nanoroughness created by the stacking of silver nanoparticles, the composite fabrics exhibited a large water contact angle of 152° and a low sliding angle of 5°. It was noted that the composite fabrics still maintain superhydrophobicity and high EMI shielding effectiveness (110 dB) even after the acid and alkali corrosion, bending, abrading, and salt fog test, respectively, demonstrating their durability under harsh environments.

Low-temperature treated polypyrrole coated cotton fabrics for efficient electromagnetic interference shielding

Low-temperature treated polypyrrole coated cotton fabrics for efficient electromagnetic interference shielding

Superhydrophobic self-extinguishing cotton fabrics for electromagnetic interference shielding and human motion detection

• Multifunctional cotton fabric has been prepared via a layer-by-layer method. • Cotton-10BL-Si shows superhydrophobic and self-extinguishing behaviors. • Cotton-10BL-Si has great potential in EMI shielding and motion sensors. • Cotton-10BL-Si shows satisfying washability and durability. Multifunctional intelligent fire-safe cotton fabric promises next-generation fire-fighting uniform and sensor applications. However, cotton fabrics' hygroscopicity and intrinsic flammability significantly impede their potential applications in industries. Herein, we report a superhydrophobic fireproof cotton fabric (PEI-APP-PEI-MXene) generated via sequential layer-by-layer deposition of polyethyleneimine (PEI), ammonium polyphosphate (APP), and titanium carbide (MXene), followed by hydrophobic treatment with silicone elastomer. Compared to untreated cotton, the treated cotton fabric with 10 polymolecular layers exhibits ∼43% and ∼42% reductions in the peak heat release rate and total heat release, respectively, a desired UL-94 V-0 rating, and a high limiting oxygen index (LOI) value of 39.5 vol.%. In addition to that, the treated fabrics displayed improved electromagnetic interference (EMI) shielding and motion-sensing abilities. The presented work provides a facile and effective surface modification approach to generate multifunctional cotton fabrics with promising practical applications.

Layer-by-Layer Self-Assembly Coating for Multi-Functionalized Fabrics: A Scientometric Analysis in CiteSpace (2005-2021).

Surface-engineered coatings have been increasingly applied to functionalize fabrics due to the ease of deposition of the coatings and their effectiveness in endowing the fabric with abundant properties. Among the surface modification methods, layer-by-layer (LbL) self-assembly has emerged as an important approach for creating multifunctional surfaces on fabrics. In this review, bibliometric analysis with the visualization analysis of LbL self-assembly coatings on fabrics was performed on publications extracted from the Web of Science (WOS) from 2005 to 2021 based on the CiteSpace software. The analysis results showed that research on LbL self-assembly coatings on fabrics has attracted much attention, and this technique has plentiful and flexible applications. Moreover, research on the LbL self-assembly method in the field of functionalization of fabrics has been summarized, which include flame retardant fabric, antibacterial fabric, ultraviolet resistant fabric, hydrophobic fabric and electromagnetic shielding fabric. It was found that the functionalization of the fabric has been changing from singularity to diversification. Based on the review, several future research directions can be proposed. The weatherability, comfort, cost and environmental friendliness should be considered when the multifunctional coatings are designed.

Effect of needle loops on shielding effectiveness of electromagnetic shielding knitted fabrics

Knitted electromagnetic shielding fabric is widely used for its excellent extensibility and permeability. However, the influence law and mechanism of the effect of needle loops on the shielding effectiveness of fabrics is still unclear. In this paper, we designed five kinds of knitted fabrics. They are plain single jersey, ‘1 × 1’ rib knitted fabric, ‘2 × 2’ rib knitted fabric, interlock knitted fabric, and full Milano structure. The shielding effectiveness adopts the flange coaxial test. Based on the electromagnetic theory principle, the influence law and mechanism of needle loop arrangement form, needle loop length, metal material, and metal amount on the shielding effectiveness of knitted fabrics were analyzed. Therefore, it can be concluded that the arrangement of needle loops dramatically influences the frequency band and shielding performance of knitted fabrics. When there is fewer intermeshing points of needle loops, the less is the shielding effectiveness of the fabric. The needle loop’s length mainly affects the shielding effectiveness of knitted fabric. The small needle loop length has great shielding effectiveness on knitted fabric. Metallic yarns with high amounts and low -resistance are beneficial for improving the shielding effect of the clothing. It provides a reference for the design, production, and related research of electromagnetic shielding knitted fabrics.

Dry and Binder-Free Deposition of Single-Walled Carbon Nanotubes on Fabrics for Thermal Regulation and Electromagnetic Interference Shielding

Dry and Binder-Free Deposition of Single-Walled Carbon Nanotubes on Fabrics for Thermal Regulation and Electromagnetic Interference Shielding

1CoFe/C Nanosheets on Hollow Carbon Fibers as Composite Fabrics for Electromagnetic Interference Shielding

¹CoFe/C Nanosheets on Hollow Carbon Fibers as Composite Fabrics for Electromagnetic Interference Shielding

A Review of Electromagnetic Shielding Fabric, Wave-Absorbing Fabric and Wave-Transparent Fabric.

As the basic materials with specific properties, fabrics have been widely applied in electromagnetic (EM) wave protection and control due to their characteristics of low density, excellent mechanical properties as well as designability. According to the different mechanisms and application scenarios on EM waves, fabrics can be divided into three types: EM shielding fabric, wave-absorbing fabric and wave-transparent fabric, which have been summarized and prospected from the aspects of mechanisms and research status, and it is believed that the current research on EM wave fabrics are imperfect in theory. Therefore, in order to meet the needs of different EM properties and application conditions, the structure of fabrics will be diversified, and more and more attentions should be paid to the research on structure of fabrics that meets EM properties, which will be conductive to guiding the development and optimization of fabrics. Furthermore, the application of fabrics in EM waves will change from 2D to 3D, from single structure to multiple structures, from large to small, as well as from heavy to light.

Interfacing MXene Flakes on a Magnetic Fiber Network as a Stretchable, Flexible, Electromagnetic Shielding Fabric.

A unique self-standing membrane composed of hierarchical thermoplastic polyurethane (TPU)/polyacrylonitrile (PAN) fibers is prepared by the electrospinning technique, followed by a simple dip-coating process. Fe3O4 nanoparticles are uniformly anchored on TPU/PAN fibers during the electrospinning process, enabling the membrane to achieve effective electromagnetic interference shielding (EMI SE) performance. Such a hybrid membrane has a high magnetization of 18.9 emu/g. When MXene (Ti3C2Tx) layers are further loaded on the TPU/PAN/Fe3O4NPs hybrid membrane, its EMI SE performance in the X band can exceed 30 dB due to the hydrogen bonds generated between the macromolecular chain of PAN and the functional group (Tx) on the surface of MXene. Simultaneously, the interfacial attraction between MXene and the TPU/PAN/Fe3O4NPs substrate is enhanced. The EMI SE mechanism of the hybrid membrane indicates that this film has great potential in the fields of wearable devices and flexible materials

Improvement of the electromagnetic properties of blended electromagnetic shielding fabric of cotton/stainless steel/polyester based on multi-layer MXenes

Blended electromagnetic shielding (EMS) fabrics of cotton/stainless steel/polyester have been widely applied. The porous structure of the fabric is the guarantee of its good comfort performance, but it also hinders the improvement of shielding efficiency and the endowing of wave absorption performance. To solve the above problems, this paper proposes a mixed resistance field based on fabric pores by the construction of multi-layer MXenes. Ti3AlC2 is etched by hydrochloric acid and lithium fluoride to generate hydrofluoric acid in situ to prepare multi-layer Ti3C2T x. The finishing experiments are designed to finish the fabric around the pores with Ti3C2T x impregnation. The enhancement effect and mechanism of the mixed resistance field on the shielding effectiveness and wave absorbing properties of the fabric are analyzed. The result shows that the multi-layer Ti3C2T x for textile finishing is prepared quickly and effectively using the proposed method. The micro media of the Ti3C2T x in the dispersion are adsorbed on the surface of various fibers, most of which are cotton fibers. The shielding effectiveness of the finished EMS fabric is improved significantly in the frequency ranges of 6.57–14 GHz and 11.97–18 GHz. The wave absorbing performances in the frequency range of 11.97–18 GHz are excellent. It is proved that the effect of the mixed resistance field of the pores was satisfactory. This paper provides a new way for the application of Ti3C2T x in EMS fabric, solves the disadvantages caused by pores, and can provide a reference for the design and production of wave absorbing EMS fabric.

Study on finishing and electromagnetic properties of electromagnetic shielding fabric based on multilayer Ti3C2T x medium

Electromagnetic shielding (EMS) fabrics have the bottlenecks of the difficulty to improve the shielding effectiveness (SE) and the lacking of absorbing properties. Finishing fabrics with Ti3C2T x are expected to be a fast and effective way to solve these problems. In this paper, two kinds of main EMS fabrics of the stainless steel blending and copper–nickel coating are selected. Ti3AlC2 is etched using hydrochloric acid and lithium fluoride in situ to generate hydrofluoric acid to prepare multilayer Ti3C2T x . The finishing experiments of the fabric with Ti3C2T x impregnation are designed. The influence of multilayer Ti3C2T x on the shielding and absorbing properties of the EMS fabric are studied. The results show that the multilayer Ti3C2T x can be prepared and dispersed as the treatment by the proposed method. For the blended fabric, the Ti3C2T x micro-media are absorbed or are infiltrated into the fibers in most cases. For the coated fabric, the Ti3C2T x micro-media are on the surface of the fabric. The SE of the blended fabric in a frequency range of 6.57–18 GHz and the copper plated nickel fabric in a frequency range of 6.57–16 GHz are enhanced. At the same time, the absorbing performances of the two types of fabrics in a high frequency band above 11.97 GHz are improved. This paper can provide a new efficient and low-cost method to improve the performance of the EMS fabric and provide a reference for the design, production and evaluation of new absorbing EMS fabrics.

Flexible and superhydrophobic carbonized cotton fabrics for effective electromagnetic interference shielding

A series of carbonized pure cotton fabrics and Ni@C nanocapsules decorated fabrics with plain-weaved structure were obtained by simple thermal treatment at different temperatures. The carbonized fabrics possess flexibility and stable hydrophobic characteristics. The carbonization temperature significantly affects the defects configuration and the migration and combination of atoms. The graphitization degree of the fabrics increases with the increase of carbonization temperature, which means an increase in electrical conductivity. The introduction of Ni@C nanocapsules results in the reaction of sulfur-philic nickel with the sulfur in the fabrics, thereby generating nickel-based sulfides with good electrical conductivity on the surface of the fabric fibers. The pure cotton fabrics carbonized at 800 °C and the Ni@C nanocapsules decorated fabrics carbonized at 700 °C and 800 °C have achieved nearly complete shielding of electromagnetic waves. The present work not only proposes an efficient process for electromagnetic interference shielding materials but also has great significance in understanding the structural origin of electromagnetic phenomena.

Flexible, breathable, and highly environmental-stable Ni/PPy/PET conductive fabrics for efficient electromagnetic interference shielding and wearable textile antennas

Lightweight and flexible multifunctional conductive fabrics with excellent environmental stability are highly demanded for electromagnetic interference (EMI) shielding and e-textiles related applications. The relationship between the fabric structure and the EM properties of conductive fabrics has aroused extensive research interest, but it is still full of challenges. Herein, warp knitted polyethylene terephthalate (WK-PET) fabric and non-woven PET (NW-PET) fabric with irregular pore structure and similar thickness are selected as substrates. Flexible Ni/PPy/PET fabrics with high EMI shielding effectiveness have been facilely fabricated by in-situ polymerization of pyrrole (Py) and subsequent electroless plating of nickel. The conductivity, EMI shielding effectiveness and the normalized effectiveness of the Ni/PPy/NW-PET fabric is 96.32 S/cm, 77.87 dB, 1600.19 dB cm2/g, respectively, which are better than those of the Ni/PPy/WK-PET (91.71 S/cm, 62.6 dB, 1037.11 dB cm2/g). A simplified fabric structure model and fractal dimension of the fabrics have been proposed in this study to reveal the relationship between the fabric structure and the EMI shielding effectiveness. It implies that the fractal dimension of a conductive fabric is highly related to its absorption EMI shielding effectiveness. It also suggests a fabric with a higher fractal dimension as a base material can provide more connected conductive networks and better EMI shielding effects for the resulting conductive fabric. Moreover, the Ni/PPy/NW-PET fabric demonstrates outstanding heat-humid stability, high bending stability and washability, as well as great potential in wearable fabric antennas. In short, this work may provide a novel idea for the development of high-performance conductive fabrics.

Preparation and evaluation of polyester-cotton/wire blended conductive woven fabrics for electromagnetic shielding

For the pursuit of conductive textiles with high electromagnetic shielding performance, specified yarns are processed with a special spinning feeding device with twist counts of 40 T, 50 T, 60 T, 70 T, 80 T, and 90 T, for Next, the optimal yarns from each group are made into SS/Pc-70 and Cu/Pc-80 conductive woven fabrics with a plain weave structure design. In addition, the surface resistivity, electromagnetic shielding effectiveness measurement and air permeability of the two conductive woven fabrics were tested and analyzed. Regarding the electromagnetic shielding performance test, the effects of the complete shielding network, the lamination layers of fabric, and lamination angle on the electromagnetic shielding performance are discussed. The test results indicate that Cu/Pc-80 woven fabrics has the lowest surface resistivity, which means it has the best electrical conductivity; Moreover, different types of metal wires provide the conductive fabrics with different levels of surface resistance. The variations in the lamination angles help attain a complete conductive network that significantly enhances the EMSE, and Cu/Pc-80 have a greater average shielding value comparatively and thus greater EMSE. For both types of conductive woven fabrics, one-layered conductive woven fabrics exhibit the maximal air permeability. As the air permeability of conductive woven fabrics is correlated with the thickness of fabrics, the greater the number of lamination layers, the lower the air permeability of the conductive fabrics.

Application of graphene in electrical resistance electromagnetic shielding fabric

Graphene is a kind of material formed by Sp2 hybridization of carbon atoms, which has been widely used in various scientific research fields in recent years. In this paper, the mechanism of electromagnetic shielding on fabrics and the recent development of resistance type electromagnetic shielding materials are introduced. The effects of graphene and metal particle composites, graphene and high conductivity polymer composites, carbon nanotubes and high conductivity polymer composites on fabrics are briefly described. The optimization of electromagnetic shielding effectiveness and the future development of shielding materials is prospected.