Sonochemically activated synthesis of gradationally complexed Ag/TEMPO-oxidized cellulose for multifunctional textiles with high electrical conductivity, super-hydrophobicity, and efficient EMI shielding

2020 ◽  
Vol 8 (40) ◽  
pp. 13990-13998 ◽  
Author(s):  
Sunghwan Hong ◽  
Seong Soo Yoo ◽  
Jun Young Lee ◽  
Pil J. Yoo

With growing concerns over electronic device malfunction and the resulting information loss caused by electromagnetic interference (EMI), extensive studies have been performed in developing EMI shielding techniques.

2019 ◽  
Vol 956 ◽  
pp. 87-98 ◽  
Author(s):  
Wei Liu ◽  
Kun Jia ◽  
Jiang Jiang Ma ◽  
Dong Hong Wang ◽  
Jian Yu Gu ◽  
...  

A series of flexible graphene/carbon nanotubes (CNTs) hybrid papers were prepared by a facile impregnation method using cellulose papers as substrate. The impregnation cycles and sequence have a great impact on microstructure, electrical conductivity and electromagnetic interference (EMI) shielding performance of graphene/CNTs hybrid papers. The results showed that the surface of cellulose papers was covered by graphene and CNTs, forming continuous conductive networks. The graphene/CNTs hybrid papers achieved a thickness range of 174.7-253.2 μm and areal density range of 26-35.7 g/m2, which presented a larger advantage than traditional EMI shielding materials. The electrical conductivity was increased from 0.33 S/cm to 7.63 S/cm with the increase of impregnation cycles from 1 to 5. Furthermore, graphene/CNTs hybrid papers delivered a high EMI shielding effectiveness of 22-32 dB in the frequency of 30-1500MHz, which was superior to single graphene or CNTs papers. Moreover, the electrical conductivity and EMI shielding effectiveness of as-prepared graphene/CNTs hybrid papers presented little decline after even bending 100 times at an angle of 180° owing to their excellent flexibility. The graphene/CNTs hybrid papers possess a huge application potential in electromagnetic compatibility (EMC) of electronic device. Key words: graphene; carbon nanotubes; electromagnetic interference shielding; cellulose paper; dielectric polarization


2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.


Nanoscale ◽  
2017 ◽  
Vol 9 (37) ◽  
pp. 14192-14200 ◽  
Author(s):  
B. Aïssa ◽  
M. Nedil ◽  
J. Kroeger ◽  
M. I. Hossain ◽  
K. Mahmoud ◽  
...  

Materials offering excellent mechanical flexibility, high electrical conductivity and electromagnetic interference (EMI) attenuation with minimal thickness are in high demand, particularly if they can be easily processed into films.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1657 ◽  
Author(s):  
Marek Neruda ◽  
Lukas Vojtech

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.


2018 ◽  
Vol 6 (38) ◽  
pp. 10292-10300 ◽  
Author(s):  
Biao Zhao ◽  
Chongxiang Zhao ◽  
Mahdi Hamidinejad ◽  
Chongda Wang ◽  
Ruosong Li ◽  
...  

The electrical conductivity and the EMI shielding properties could be effectively tuned by the foaming degree.


2020 ◽  
Vol 32 (10) ◽  
pp. 1140-1149
Author(s):  
Jiahong Tang ◽  
Fan Ye ◽  
Yeping Xie ◽  
Pengju Liu

Constructing the segregated networks is an efficient strategy to simultaneously achieve the high electrical conductivity and electromagnetic interference (EMI) shielding performance in conductive polymer composites (CPCs). Herein, an advanced molding technique based on microwave (MW)-assisted sintering was proposed to prepare the segregated ultrahigh molecular weight polyethylene/carbon nanotube (UHMWPE/CNT) composites. Scanning electron microscopy and optical microscopy images indicated that CNTs enriched on the surfaces of UHMWPE granules through ball milling, and the clear and complete conductive networks were observed in UHMWPE/CNT composites in the following MW sintering process, revealing that a perfect segregated structure was successfully constructed. The segregated UHMWPE/CNT composites exhibited an excellent electrical conductivity and EMI shielding performance of 49.3 S/m and 50 dB, respectively, along with a low percolation threshold of 0.10 vol%. Meanwhile, benefiting from the volumetric heating, an ideal mechanical property was also obtained in prepared composite by MW sintering. Compared with the conventional molding method, MW-assisted sintering shows its unique advantages, including better structural construction, shorter processing time, and lower energy consumption, which provides an efficient and environment-friendly method to fabricate CPCs with superior conductive and EMI shielding performance.


2002 ◽  
Vol 126 (2-3) ◽  
pp. 233-239 ◽  
Author(s):  
M.S. Kim ◽  
H.K. Kim ◽  
S.W. Byun ◽  
S.H. Jeong ◽  
Y.K. Hong ◽  
...  

2021 ◽  
Vol 9 (1) ◽  
pp. 214-222
Author(s):  
Xiaojing Liu ◽  
Wenyu Wu ◽  
Bin Guo ◽  
Minghao Cui ◽  
Huaxin Ma ◽  
...  

Graphene films prepared through a self-assembly of graphene oxide and its derivatives have been recently explored for electromagnetic interference (EMI) shielding applications.


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