Highly Bendable and Durable Waterproof Paper for Ultra-High Electromagnetic Interference Shielding

An efficient electromagnetic interference (EMI) shielding paper with excellent water repellency and mechanical flexibility has been developed, by assembling silver nanowires (AgNWs) and hydrophobic inorganic ceramic on the cellulose paper, via a facile dip-coating preparation. Scanning electron microscope (SEM) observations confirmed that AgNWs were interconnected and densely coated on both sides of the cellulose fiber, which endows the as-prepared paper with high conductivity (33.69 S/cm in-plane direction) at a low AgNW area density of 0.13 mg/cm2. Owing to multiple reflections and scattering between the two outer highly conductive surfaces, the obtained composite presented a high EMI shielding effectiveness (EMI SE) of up to 46 dB against the X band, and ultrahigh specific EMI SE of 271.2 dB mm–1. Moreover, the prepared hydrophobic AgNW/cellulose (H-AgNW/cellulose) composite paper could also maintain high EMI SE and extraordinary waterproofness (water contact angle > 140°) by suffering dozens of bending tests or one thousand peeling tests. Overall, such a multifunctional paper might have practical applications in packaging conductive components and can be used as EMI shielding elements in advanced application areas, even under harsh conditions.

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Polyaniline-Stannous Oxide Composites: Novel Material for Broadband EMI Shielding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.488-489.557 ◽

2012 ◽

Vol 488-489 ◽

pp. 557-561 ◽

Cited By ~ 8

Author(s):

Muhammad Faisal ◽

Syed Khasim

Keyword(s):

Electromagnetic Interference ◽

Chemical Oxidation ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Practical Applications ◽

Stannous Oxide ◽

Emi Shielding Effectiveness ◽

X Band ◽

Potential Applications ◽

Emi Se

Insitu polymerization of aniline was carried out in the presence of stannous oxide (SnO) to synthesize Polyaniline (PAni)/SnO composites by chemical oxidation method. The surface morphology of the composites were studied by scanning electron microscopy (SEM).The electromagnetic interference (EMI) shielding properties of the composites were investigated for different wt % of SnO (10,20,30,40 and 50 wt%) in PAni. The EMI measurements were carried out in the frequency range from 8.2 to 12.4 GHz (X-band), which is relevant for practical applications. EMI shielding effectiveness (EMI SE), microwave absorption and reflection, the influence of SnO concentration in PAni on EMI SE of the composites are reported. The composites exhibit EMI SE value of -18 to -23 dB. The absorption dominated EMI SE of these composites indicates the potential applications of these materials for microwave attenuation in the X-band.

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Interface Engineered Microcellular Magnetic Conductive Polyurethane Nanocomposite Foams for Electromagnetic Interference Shielding

Nano-Micro Letters ◽

10.1007/s40820-021-00677-5 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Guolong Sang ◽

Pei Xu ◽

Tong Yan ◽

Vignesh Murugadoss ◽

Nithesh Naik ◽

...

Keyword(s):

Electromagnetic Interference ◽

Magnetic Loss ◽

Interfacial Polarization ◽

Conductive Network ◽

Shielding Effectiveness ◽

Electromagnetic Interference Shielding ◽

Multiple Reflections ◽

Conduction Loss ◽

Composite Foams ◽

Emi Se

Abstract Lightweight microcellular polyurethane (TPU)/carbon nanotubes (CNTs)/ nickel-coated CNTs (Ni@CNTs)/polymerizable ionic liquid copolymer (PIL) composite foams are prepared by non-solvent induced phase separation (NIPS). CNTs and Ni@CNTs modified by PIL provide more heterogeneous nucleation sites and inhibit the aggregation and combination of microcellular structure. Compared with TPU/CNTs, the TPU/CNTs/PIL and TPU/CNTs/Ni@CNTs/PIL composite foams with smaller microcellular structures have a high electromagnetic interference shielding effectiveness (EMI SE). The evaporate time regulates the microcellular structure, improves the conductive network of composite foams and reduces the microcellular size, which strengthens the multiple reflections of electromagnetic wave. The TPU/10CNTs/10Ni@CNTs/PIL foam exhibits slightly higher SE values (69.9 dB) compared with TPU/20CNTs/PIL foam (53.3 dB). The highest specific EMI SE of TPU/20CNTs/PIL and TPU/10CNTs/10Ni@CNTs/PIL reaches up to 187.2 and 211.5 dB/(g cm−3), respectively. The polarization losses caused by interfacial polarization between TPU substrates and conductive fillers, conduction loss caused by conductive network of fillers and magnetic loss caused by Ni@CNT synergistically attenuate the microwave energy.

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

Nano-Micro Letters ◽

10.1007/s40820-021-00597-4 ◽

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.

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A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High-Efficient Electromagnetic Interference Shielding

Nano-Micro Letters ◽

10.1007/s40820-021-00693-5 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Ting Wang ◽

Wei-Wei Kong ◽

Wan-Cheng Yu ◽

Jie-Feng Gao ◽

Kun Dai ◽

...

Keyword(s):

Electromagnetic Interference ◽

Diels Alder ◽

Electrostatic Attraction ◽

List Type ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Electromagnetic Interference Shielding ◽

Elongation At Break ◽

High Efficient ◽

Emi Se

Highlights The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. Abstract It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels–Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.

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Electromagnetic interference shielding effectiveness of polypyrrole-silver nanocomposite films on silane-modified flexible sheet

High Performance Polymers ◽

10.1177/09540083211064535 ◽

2021 ◽

pp. 095400832110645

Author(s):

Karim Benzaoui ◽

Achour Ales ◽

Ahmed Mekki ◽

Abdelhalim Zaoui ◽

Boudjemaa Bouaouina ◽

...

Keyword(s):

Surface Treatment ◽

Electromagnetic Interference ◽

Nanocomposite Films ◽

Electrical Characteristics ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Electromagnetic Interference Shielding ◽

Silver Nanocomposite ◽

Electromagnetic Interference Shielding Effectiveness ◽

Emi Se

The conventional electromagnetic interference (EMI) shielding materials are being gradually replaced by a new generation of supported conducting polymer composites (CPC) films due to their many advantages. This work presents a contribution on the effects of silane surface–modified flexible polypyrrole-silver nanocomposite films on the electromagnetic interference shielding effectiveness (EMI-SE). Thus, the UV-polymerization was used to in-situ deposit the PPy-Ag on the biaxial oriented polyethylene terephthalate (BOPET) flexible substrates whose surfaces were treated by 3-aminopropyltrimethoxysilane (APTMS). X-ray Photoelectron Spectroscopy (XPS) analyzes confirmed the APTMS grafting procedure. Structural, morphological, thermal, and electrical characteristics of the prepared films were correlated to the effect of substrate surface treatment. Thereafter, EMI-SE measurements of the elaborated films were carried out as per ASTM D4935 standard for a wide frequency band extending from 50 MHz to 18 GHz. The obtained results confirmed that the APTMS-treated BOPET film exhibit higher EMI shielding performance and better electrical characteristics compared to the untreated film. In fact, a 32% enhancement of EMI-SE was noted for the treated films compared to the untreated ones. Overall, these results put forward the role played by the surface treatment in strengthening the position of flexible PPy-Ag supported films as high-performance materials in electronic devices and electromagnetic interference shielding applications.

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Superhydrophobic/Flame Retardant/EMI Shielding Fabrics: Manufacturing Techniques and Property Evaluations

Applied Sciences ◽

10.3390/app9091914 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1914 ◽

Cited By ~ 1

Author(s):

Hao-Kai Peng ◽

Yanting Wang ◽

Ting-Ting Li ◽

Ching-Wen Lou ◽

Qi He ◽

...

Keyword(s):

Flame Retardant ◽

Electromagnetic Interference ◽

Core Material ◽

Shielding Effect ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Spun Yarn ◽

Hydrophobic Treatment ◽

Fabric Surface ◽

Emi Se

Electromagnetic pollution interferes with electronic equipment in proximity and jeopardizes human health, which urges the development of electromagnetic interference (EMI) shielding materials. It is urgent to develop electromagnetic interference (EMI) shielding materials. However, the preparation of materials with superhydrophobicity, flame retardancy and EMI shielding properties is still challenging. In this study, we invented a core-spun yarn feeding device, which uses polysulfonamide (PSA) roving as a coating material and stainless steel wire as the core material to prepare a conductive core-spun yarn, which solves the problem of the wire having an easily exposed fabric surface. The finally prepared conductive fabric was subjected to Waterproof 2P hydrophobic treatment to form a superhydrophobic flame-retardant EMI shielding fabric. The results show that the hydrophobic treatment creates a thin film over the woven fabrics, and the contact angle of the fabric surface can reach 155°. The hydrophobic treatment will not damage the shielding effect and slightly increase the dB value. The average dB value of PSA-SS-1’ and PSA-SS-2’ are increased by 0.82 dB and 1.92 dB, respectively. When composed of conductive wrapped yarns for both the warp and weft yarns, the electromagnetic interference shielding effectiveness (EMI SE) of conductive fabrics is beyond 30 dB at 0–3000 MHz and the burnt depth is shorter than 40 mm. As for real applications, superhydrophobic/flame retardant/EMI SE fabrics can be used in a moist and complex environment with retaining conductivity and shielding effectiveness.

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Carbonization of Graphene-Doped Isocyanate-Based Polyimide Foams to Achieve Carbon Foams with Excellent Electromagnetic Interference Shielding Performance

Materials ◽

10.3390/ma14247551 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7551

Author(s):

Hui Jing ◽

Zongnan Miao ◽

Zhong Zeng ◽

Hui Liu ◽

Shengtai Zhou ◽

...

Keyword(s):

Electrical Conductivity ◽

Electromagnetic Interference ◽

Carbonization Temperature ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Emi Shielding Effectiveness ◽

Graphitization Degree ◽

Carbon Foams ◽

Potential Applications ◽

Emi Se

Lightweight carbon foams with excellent electromagnetic interference (EMI) shielding performance were prepared by carbonization process, using isocyanate-based polyimide foams as carbon precursors. The influence of carbonization temperature and graphene-doping on the morphological, electrical and EMI shielding effectiveness (SE) of corresponding carbon foams was studied in detail. Results showed that the addition of graphene was beneficial to the improvement of electrical conductivity and EMI shielding performance of carbon foams. The electrical conductivity of carbon foams increased with the carbonization temperature which was related to the increase of graphitization degree. Collapse of foam cells was observed at higher carbonization temperatures, which was detrimental to the overall EMI SE. The optimal carbonization temperature was found at 1100 °C and the carbon foams obtained from 0.5 wt% graphene-doped foams exhibited a specific EMI SE of 2886 dB/(g/cm3), which shows potential applications in fields such as aerospace, aeronautics and electronics.

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Layered Foam/Film Polymer Nanocomposites with Highly Efficient EMI Shielding Properties and Ultralow Reflection

Nano-Micro Letters ◽

10.1007/s40820-021-00759-4 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Li Ma ◽

Mahdi Hamidinejad ◽

Biao Zhao ◽

Caiyun Liang ◽

Chul B. Park

Keyword(s):

Electromagnetic Interference ◽

High Efficiency ◽

Wave Attenuation ◽

Impedance Matching ◽

Film Structure ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Multiple Reflections ◽

Emi Shielding Effectiveness ◽

Foam Film

AbstractLightweight, high-efficiency and low reflection electromagnetic interference (EMI) shielding polymer composites are greatly desired for addressing the challenge of ever-increasing electromagnetic pollution. Lightweight layered foam/film PVDF nanocomposites with efficient EMI shielding effectiveness and ultralow reflection power were fabricated by physical foaming. The unique layered foam/film structure was composed of PVDF/SiCnw/MXene (Ti3C2Tx) composite foam as absorption layer and highly conductive PVDF/MWCNT/GnPs composite film as a reflection layer. The foam layer with numerous heterogeneous interfaces developed between the SiC nanowires (SiCnw) and 2D MXene nanosheets imparted superior EM wave attenuation capability. Furthermore, the microcellular structure effectively tuned the impedance matching and prolonged the wave propagating path by internal scattering and multiple reflections. Meanwhile, the highly conductive PVDF/MWCNT/GnPs composite (~ 220 S m−1) exhibited superior reflectivity (R) of 0.95. The tailored structure in the layered foam/film PVDF nanocomposite exhibited an EMI SE of 32.6 dB and a low reflection bandwidth of 4 GHz (R < 0.1) over the Ku-band (12.4 − 18.0 GHz) at a thickness of 1.95 mm. A peak SER of 3.1 × 10–4 dB was obtained which corresponds to only 0.0022% reflection efficiency. In consequence, this study introduces a feasible approach to develop lightweight, high-efficiency EMI shielding materials with ultralow reflection for emerging applications.

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Flexible GnPs/EPDM with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Properties

NANO ◽

10.1142/s1793292019500759 ◽

2019 ◽

Vol 14 (06) ◽

pp. 1950075 ◽

Cited By ~ 2

Author(s):

Shaowei Lu ◽

Yaoyao Bai ◽

Jijie Wang ◽

Dandan Chen ◽

Keming Ma ◽

...

Keyword(s):

Thermal Conductivity ◽

Electromagnetic Interference ◽

Rubber Matrix ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Emi Shielding Effectiveness ◽

X Band ◽

Cost Efficient ◽

Emi Se ◽

Shielding Material

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8[Formula: see text]wt.% GnPs/EPDM with only 0.3[Formula: see text]mm in thickness shows excellent electrical conductivity (28.3[Formula: see text]S/m), thermal conductivity (0.79[Formula: see text]W/m[Formula: see text]K) and good mechanical properties. Besides, the 8[Formula: see text]wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33[Formula: see text]dB in the X-band (8.2–12.4[Formula: see text]GHz) and 35[Formula: see text]dB in the Ku-band (12.4–18[Formula: see text]GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons.

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Short Shaped Copper Fibers in an Epoxy Matrix: Their Multifunctional Use — Fracture and Impact Toughening and EMI Shielding

Materials ◽

10.1115/imece2004-60405 ◽

2004 ◽

Cited By ~ 1

Author(s):

Robert C. Wetherhold ◽

Renee M. Bagwell ◽

Joseph M. McManaman

Keyword(s):

Impact Toughness ◽

Electromagnetic Interference ◽

Lower Number ◽

Shielding Effectiveness ◽

Emi Shielding ◽

Fiber Pullout ◽

The Matrix ◽

The Impact ◽

Emi Se ◽

Shaped Fibers

Previous research has shown that short shaped copper fibers can significantly increase the fracture toughness of a thermoset matrix composite. This paper considers the effectiveness of adding these same short shaped copper fibers to improve the composite’s impact toughness. Further, the electromagnetic interference (EMI) shielding effectiveness (SE) of these shaped copper fibers will be analyzed. The matrices used in the impact experiments were two different types of epoxy, a low shrinkage epoxy (LS) and a high shrinkage epoxy (HS). Fiber shapes and lengths were chosen based on previous single fiber pullout experiments. The following shaped fibers were used: straight, flat end-impacted, rippled, and end-oxidized. The two fiber lengths tested were 6mm and 10mm. Results indicate that the largest influence on impact toughness is from the matrix fracture behavior. When the matrix failed around the fibers, the impact toughness was significantly less compared to matrices with the same fibers that had a planar fracture at the notch during impact. Fiber end modification and to a lesser extent the fiber length both also had an effect on the fiber pullout behavior and resulting toughness. Comparing the end-modified fibers to straight fibers, the largest increase in impact toughness was 17%. The matrix used for the EMI shielding experiments was HS epoxy and two fiber diameters were tested: 0.325 mm and 0.162 mm. The fiber shapes used in the experiments were: straight, flat end-impacted, rippled, and acid roughened. An EMI SE of > 40 dB at 1.5 GHz was attained using 15vol% of the 0.162 mm diameter shaped fibers. The composites with 15vol% of the 0.325 mm diameter shaped fibers showed poor EMI SE, < 20 dB, due to large fiber diameter that results in a lower skin depth volume and a lower number of fibers which results in a lower number of conducting paths for attenuation through the composite. Results indicate that besides improving the fracture and impact toughness of a thermoset polymer matrix, short shaped copper fibers can also significantly improve the EMI SE of the composite, resulting in a multifunctional material.

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