scholarly journals Ultrathin Multilayer Textile Structure with Enhanced EMI Shielding and Air-Permeable Properties

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4176
Author(s):  
Shi Hu ◽  
Dan Wang ◽  
Aravin Prince Periyasamy ◽  
Dana Kremenakova ◽  
Jiri Militky ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Single Layer ◽  
Electromagnetic Shielding ◽  
Shielding Effect ◽  
Material Surface ◽  
Test Results ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Electromagnetic Shielding Effectiveness

A textile material’s electromagnetic interference (EMI) shielding effectiveness mainly depends on the material’s electrical conductivity and porosity. Enhancing the conductivity of the material surface can effectively improve the electromagnetic shielding effectiveness. However, the use of highly conductive materials increases production cost, and limits the enhancement of electromagnetic shielding effectiveness. This work aims to improve the EMI shielding effectiveness (EMSE) by using an ultrathin multilayer structure and the air-permeable textile MEFTEX. MEFTEX is a copper-coated non-woven ultrathin fabric. The single-layer MEFTEX SE test results show that the higher its mass per unit area (MEFTEX 30), the better its SE property between 56.14 dB and 62.53 dB in the frequency band 30 MHz–1.5 GHz. Through comparative testing of three groups samples, a higher electromagnetic shielding effect is obtained via multilayer structures due to the increase in thickness and decrease of volume electrical resistivity. Compared to a single layer, the EMI shielding effectiveness of five layers of MEFTEX increases by 44.27–83.8%. Due to its ultrathin and porous structure, and considering the balance from porosity and SE, MEFTEX 10 with three to four layers can still maintain air permeability from 2942 L/m2/s–3658 L/m2/s.

Mechanical performance and electromagnetic shielding effectiveness of composites based on Ag-plating cellulose micro-nano fibers and epoxy

2017 ◽  
Vol 37 (8) ◽  
pp. 805-813 ◽  
Author(s):  
Yu Wang ◽  
Jin Tian Huang
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Interference ◽  
Mechanical Performance ◽  
Oxide Phase ◽  
Cellulose Fibers ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Emi Shielding Effectiveness ◽  
Nano Cellulose ◽  
Electromagnetic Shielding Effectiveness

Abstract Mechanical and electromagnetic interference shielding composites containing Ag-plating micro-nano cellulose fibers (ANCFs) were prepared as multifunctional materials. ANCFs, as electromagnetic wave reflection filler containing micro-nano cellulose fibers (NCFs) used as the structural component to reinforce the mechanical strength and Ag enhancing electromagnetic shielding effectiveness, were prepared by electroless Ag-plating technology on NCFs surfaces. Ag coating had a thickness of 60 µm without the oxide phase detected. The incorporation of 5 wt % ANCFs into epoxy (EP) substrate yielded impact strength and flexural strength of 1.84 kJ/m2 and 41.6 MPa, which is approximately 2.4 times and 1.41 times higher than EP. The ANCFs-EP composite performed an electromagnetic shielding effectiveness of 34–25 dB at a frequency of 90 kHz in the electromagnetic wave; the EMI shielding effectiveness was improved obviously up to 34 dB, which can meet the requirement of general places.

Preparation and properties of graphene aerogel/cotton composite flexible fabric with electromagnetic interference (EMI) shielding function

2021 ◽  
pp. 152808372198927
Author(s):  
Peng Wang ◽  
Shuqiang Liu ◽  
Man Zhang ◽  
Gaihong Wu ◽  
Kaiwen Wang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Waterborne Polyurethane ◽  
Development Trend ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Graphene Aerogel ◽  
Emi Shielding Effectiveness ◽  
Aerogel Composite ◽  
Electromagnetic Pollution

In order to alleviate the problems caused by electromagnetic pollution and simultaneously adapt to the future development trend of flexible wearable electronic equipment, it is high time to focus on the research of light weight, flexible and efficient electromagnetic interference (EMI) shielding material. A graphene aerogel composite EMI shielding composite fabric was prepared by combining graphene aerogel with fabric through the connection of waterborne polyurethane. The influence of aerogel amount on the EMI shielding function of fabric was discussed, and the waterborne polyurethane dosage on fabric mechanics and fabric style was also investigated. The result shows the composite fabric EMI shielding effectiveness reached 28 dB when the graphene aerogel amount was 25 mL (only 0.066 mL/cm2), which has satisfied the civilian requirements (20 dB). A good adhesion fastness between graphene and cotton fabric was obtained and the mechanical strength was also improved when the content of waterborne polyurethane was 20 mL. Graphene aerogel electromagnetic shielding composite fabric with good electromagnetic shielding performance and less consumption of nano carbon materials will have a good industrial application prospect.

scholarly journals A Novel Processing for CNT-Reinforced Mg-Matrix Laminated Composites to Enhance the Electromagnetic Shielding Property

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1030 ◽  
Author(s):  
Wanshun Zhang ◽  
Hongyang Zhao ◽  
Xiaodong Hu ◽  
Dongying Ju
Keyword(s):  
Electrophoretic Deposition ◽  
Electromagnetic Interference ◽  
Deposition Time ◽  
Laminated Composites ◽  
Electromagnetic Shielding ◽  
Matrix Composites ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Plane Wave ◽  
Emi Shielding Effectiveness

The microstructure, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of CNTs/Mg Matrix composites prepared by accumulative roll bonding (ARB) were systematically investigated to understand the effects of CNTs on the electromagnetic interference shielding effectiveness property of magnesium. A model based on the shielding of the electromagnetic plane wave was used to theoretically discuss the EMI shielding mechanisms of ARB-processed composites. The experimental results indicated that the methods were feasible to prepare laminated composites. The SE of the material increased gradually with the increase of electrophoretic deposition time. When the electrophoretic deposition time reached 8 min, the value of SE remained 87–95 dB in the frequency range of 8.2–12.4 GHz. The increase in SE was mainly attributed to the improvement in the reflection and multiple reflection losses of incident electromagnetic wave due to the increased amounts of CNTs and interfaces. The methods provided an efficient strategy to produce laminated metal matrix composites with high electromagnetic shielding properties.

A highly stretchable, easily processed and robust metal wire-containing woven fabric with strain-enhanced electromagnetic shielding effectiveness

2021 ◽  
pp. 004051752199489 ◽  
Author(s):  
Yong Wang ◽  
Stuart Gordon ◽  
Weidong Yu ◽  
Zongqian Wang
Keyword(s):  
Electromagnetic Interference ◽  
Specular Reflection ◽  
Electronic Devices ◽  
Single Layer ◽  
Electromagnetic Shielding ◽  
Woven Fabric ◽  
Shielding Effectiveness ◽  
Fabric Structure ◽  
Highly Stretchable ◽  
Electromagnetic Shielding Effectiveness

Textiles that contain integrated conducting components are drawing attention for their ability to mitigate electromagnetic radiation pollution. Maintaining effective and robust electromagnetic shielding effectiveness (EMSE) under different modes, e.g. stretching, bending and washing, is of importance in protecting humans and information-sensitive electronic devices from exposure to electromagnetic interference. In this work, a weft-stretchable, conductive fabric (W-SCF) was specially manufactured for electromagnetic shielding characterization by integrating stainless steel filament (SSF) in the weft direction. The results demonstrate that our as-prepared W-SCF was effective for shielding purpose with its EMSE dependent on the orientation of the SSF within the fabric structure. Specular reflection caused by the close arrangement of the SSF and the lower electrical resistance of the fabric on per unit area basis were responsible for the enhanced shielding properties when the fabric was stretched. Furthermore, using the fabric in a 90°/90° laminated form improved the EMSE values compared with a single layer and a 0°/90° laminated versions. Importantly, the W-SCF exhibited resistance to 10 laundering cycles, 20 stretching cycles (at 25% extension), 50 bending cycles and 100 abrasion cycles, demonstrating its robustness and durability. This work is believed to take a new step in development of reliable and advance shielding materials for special protective application.

scholarly journals Ultrathin, Lightweight, and Flexible CNT Buckypaper Enhanced Using MXenes for Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Rongliang Yang ◽  
Xuchun Gui ◽  
Li Yao ◽  
Qingmei Hu ◽  
Leilei Yang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Electronic Devices ◽  
Deposition Process ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
X Band ◽  
Wearable Electronic Devices ◽  
Emi Se

AbstractLightweight, flexibility, and low thickness are urgent requirements for next-generation high-performance electromagnetic interference (EMI) shielding materials for catering to the demand for smart and wearable electronic devices. Although several efforts have focused on constructing porous and flexible conductive films or aerogels, few studies have achieved a balance in terms of density, thickness, flexibility, and EMI shielding effectiveness (SE). Herein, an ultrathin, lightweight, and flexible carbon nanotube (CNT) buckypaper enhanced using MXenes (Ti3C2Tx) for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process. The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100 μm. The hybrid buckypaper with an MXene content of 49.4 wt% exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15 μm, which is 105% higher than that of pristine CNT buckypaper. Furthermore, an average specific SE value of 5.7 × 104 dB cm2 g−1 is exhibited in the 5-μm hybrid buckypaper. Thus, this assembly process proves promising for the construction of ultrathin, flexible, and high-performance EMI shielding films for application in electronic devices and wireless communications.

scholarly journals Electromagnetic Shielding Effectiveness of Woven Fabrics with High Electrical Conductivity: Complete Derivation and Verification of Analytical Model

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1657 ◽  
Author(s):  
Marek Neruda ◽  
Lukas Vojtech
Keyword(s):  
Electrical Conductivity ◽  
Analytical Model ◽  
Electromagnetic Interference ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
High Electrical Conductivity ◽  
Shielding Effectiveness ◽  
Textile Composite ◽  
A Value ◽  
Electromagnetic Shielding Effectiveness

In this paper, electromagnetic shielding effectiveness of woven fabrics with high electrical conductivity is investigated. Electromagnetic interference-shielding woven-textile composite materials were developed from a highly electrically conductive blend of polyester and the coated yarns of Au on a polyamide base. A complete analytical model of the electromagnetic shielding effectiveness of the materials with apertures is derived in detail, including foil, material with one aperture, and material with multiple apertures (fabrics). The derived analytical model is compared for fabrics with measurement of real samples. The key finding of the research is that the presented analytical model expands the shielding theory and is valid for woven fabrics manufactured from mixed and coated yarns with a value of electrical conductivity equal to and/or higher than σ = 244 S/m and an excellent electromagnetic shielding effectiveness value of 25–50 dB at 0.03–1.5 GHz, which makes it a promising candidate for application in electromagnetic interference (EMI) shielding.

scholarly journals Electromagnetic Interference Shielding Performance Enhancement of Stretchable Transparent Conducting Silver Nanowire Networks with Graphene Encapsulation

2021 ◽  
Author(s):  
Siyi Yan ◽  
Peng Li ◽  
Zhongshi Ju ◽  
He Chen ◽  
Jiangang Ma
Keyword(s):  
Electromagnetic Interference ◽  
Performance Enhancement ◽  
Mechanical Stability ◽  
Silver Nanowire ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Dielectric Polarization ◽  
Emi Shielding Effectiveness ◽  
Graphene Films ◽  
Transparent Conducting

Abstract Silver nanowire (AgNW) networks are promising transparent conducting materials for electromagnetic interference (EMI) shielding and diverse optoelectronic devices. However, the poor contact between adjacent AgNWs leads to low electrical conductivity and weak mechanical stability of AgNW networks, which are limiting the practical application of these electronics. Here we report an efficient strategy to improve the overall performance of AgNW networks, in which the AgNW networks are sandwiched between two layers of graphene films. The graphene films improve the contact of overlapped AgNWs and bridge the discrete AgNWs, and thus increase the conductivity of graphene/AgNWs/graphene (GAG) films. Microwave permittivity measurements together with mechanism analyses reveal that the graphene films can enhance the EMI shielding effectiveness of AgNW networks through offering extra conduction loss, multiple dielectric polarization centers and multi-reflection processes. As a result, the GAG film with an average transmittance of 88% exhibits a sheet resistance lower than 15 Ω sq− 1 and an EMI shielding effectiveness of 31 dB (in the frequency range of 8.2‒12.4 GHz) after repeated stretching and release at a strain of 40%. Such a total performance is superior to that of most of as-reported transparent conductors. The GAG films therefore show application potential in the age of Internet of Things that electromagnetic radiation pollutions are everywhere.

Flexible, conductive, porous, fibrillar polymer–gold nanocomposites with enhanced electromagnetic interference shielding and mechanical properties

2017 ◽  
Vol 5 (5) ◽  
pp. 1095-1105 ◽  
Author(s):  
Jun Li ◽  
Hu Liu ◽  
Jiang Guo ◽  
Zhen Hu ◽  
Zhijiang Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gold Nanoparticles ◽  
Self Assembly ◽  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Conductive Nanocomposites ◽  
Gold Nanocomposites

Flexible lightweight conductive nanocomposites prepared by self-assembly of gold nanoparticles on charged polymer nanofibers show enhanced EMI shielding effectiveness and mechanical properties.

Electromagnetic Shielding Effectiveness and Manufacturing Technique of Metal Complex Fabrics

2014 ◽  
Vol 496-500 ◽  
pp. 472-475
Author(s):  
Ching Wen Lou ◽  
An Pang Chen ◽  
Ting An Lin ◽  
Ya Yuan Chuang ◽  
Jia Horng Lin
Keyword(s):  
Metal Complex ◽  
Life Time ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Test Results ◽  
Test Frequency ◽  
Shielding Effectiveness ◽  
Conductive Composite ◽  
Composite Yarn ◽  
Electromagnetic Shielding Effectiveness

In the research, The electromagnetic interferences (EMI) have drastically increased and can disrupt and reduce the life time and the efficiency of devices. Therefore, the electromagnetic shielding problem is become the important issue. In the research, Ni wire and Cu wire (Floodlit Enterprise Co., Ltd.) were used to make the Ni conductive composite yarn and Cu conductive composite yarn via an electrical covering machine. And the Cu conductive composite yarn was fabricated to the woven fabrics with the plain weaving. The test results revealed that the EMSE of the W/K/W complex fabrics have stable EMSE than the W/W/W complex fabrics when the laminated at the same direction. The W/90W/W complex woven fabrics were shown the best EMSE of 46.25 dB, which the test frequency is 1800 MHz.

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