The influence of single-walled carbon nanotube structure on the electromagnetic interference shielding efficiency of its epoxy composites

Huang, Yi; Li, Ning; Ma, Yanfeng; Du, Feng; Li, Feifei; He, Xiaobo; Lin, Xiuping; Gao, Hongjun; Chen, Yongsheng

doi:10.1016/j.carbon.2007.04.016

Cited by 530 publications

(243 citation statements)

References 31 publications

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“…While recently, ICP composites with ferrite, singlewalled carbon nanotube ͑CNT͒, and multiwalled CNT have been reported as EMI shielding material with SE of ϳ30 dB having high thickness. [7][8][9] The higher SE of PBT results from the combined effect of the nanoparticles and the polymer matrix. The contribution to the microwave absorption comes mainly from the magnetic losses in barium ferrite and dielectric losses in TiO 2 and polyaniline.…”

Section: Introductionmentioning

confidence: 99%

Conjugated polymer nanocomposites: Synthesis, dielectric, and microwave absorption studies

Ohlan

Singh

Chandra

et al. 2009

Journal of Applied Physics

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Nanocomposites of polyaniline with barium ferrite and titanium dioxide ͑TiO 2 ͒ are synthesized via in situ emulsion polymerization. The transmission electron microscopy ͑TEM͒ and high resolution TEM result shows the formation of array of nanoparticles encapsulated within the polymer chains during the synthesis process. The high value of microwave absorption, 58 dB ͑Ͼ99.999% attenuation͒ results from the combined effect of the nanoparticles and the polymer matrix. The amount of barium ferrite has the profound effect on permittivity ͑ ͒, permeability ͑ ͒, and microwave absorption of the nanocomposite. The contribution to the absorption value comes mainly due the magnetic losses ͑ Љ͒ in barium ferrite and dielectric losses ͑ Љ͒ in TiO 2 and polyaniline.

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Section: Introductionmentioning

confidence: 99%

Conjugated polymer nanocomposites: Synthesis, dielectric, and microwave absorption studies

Ohlan

Singh

Chandra

et al. 2009

Journal of Applied Physics

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“…The MWNTs were prepared using the CVD technique [18]. A solution of ferrocene in toluene (in an appropriate ratio) is injected into a two-stage furnace whose reaction zone is maintained at 750 C. Argon is used as the carrier gas and its flow rate is adjusted in such a manner that the maximum quantity of precursor is consumed in the reaction zone.…”

Section: Methodsmentioning

confidence: 99%

“…Also, from the SEM micrographs, it can be observed that nanotubes are quite long. This is a beneficial feature for the nanocomposites because longer nanotubes exhibit much lower percolation thresholds in a composite system as compared to shorter nanotubes [18]. Also, it can be observed from the SEM micrographs that the nanotubes are randomly distributed and not aligned in films.…”

Section: Morphological Characterisationmentioning

confidence: 99%

Low electrical percolation threshold and PL quenching in solution-blended MWNT–MEH PPV nanocomposites

Bansal

Srivastava

Lal

et al. 2010

Journal of Experimental Nanoscience

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Pristine multiwall carbon nanotubes (MWNT) (synthesised using CVD approach) and poly[2-methoxy-5-(2 0 -ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH PPV) based composites were prepared using a solution blending approach by employing various nanotube weight fractions. The prepared composites have been characterised using SEM, AFM, PL spectroscopy, UV-Vis studies and I-V characterisation. Increase in MWNT concentration has been found to quench the PL spectra of the composites suggesting photoinduced electron transfer from polymer to MWNT. The increase in MWNT concentration also increases the absorption of the composites. PL quenching and increase in absorption are desirable attributes for the design of photovoltaic systems. Also, the electrical conductivities of the composites can be described by the scaling law based on percolation theory and based upon the scaling law, a low electrical percolation threshold value (0.5 wt%) has been obtained for this composite system. The value of t (critical exponent) based on percolation theory is found to be 1.11. The low value of t is attributed to the aggregation and bundling of nanotubes in the prepared composites, as is evident from SEM and AFM micrographs. The turnon voltage is also found to be reduced in the case of polymer-nanotube composite system as compared to the pristine polymer system. Also, it has been observed that at higher weight percentages, the MWNTs form an immensely dense network and act as nanometric heat sinks, thus preventing the build up of large thermal effects, caused by the increased current in the pixels at higher voltages. Analysis of these optical and electrical properties is important before utilising the composite in organic electronics applications, in order to obtain more scientifically correct and repeatable results with fabricated devices.

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“…Therefore, this sponge material would have a great po-tential for microwave-frequency applications that need negli-gible reflection and great absorption when combined in a multilayered structure that could prevent the wave to be re-flected at the input interface. their aspect ratio [7]. In this context, it has been shown that values of SE around 20 dB (desired value for most emerging applications) could be reached with 15 wt% of carbon black (CB), 5-10 wt% carbon nanofibres (CNF) and only 2-3 wt% of multi-walled carbon nanotubes (MWCNTs) [8].…”

Section: Introductionmentioning

confidence: 99%

Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range

Crespo

González

Elías

et al. 2014

Phys. Status Solidi RRL

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CVD synthesised CNT flexible sponge with density lower than 0.02 g cm–3 has been found to serve as high performance EMI shielding material without the aid of any polymer infiltration or impregnation. Due to its extreme lightweight, the specific SE of the CNT‐sponge was found to be as high as 1100 dB cm3 g–1, having a total SE above 20 dB in the whole 1–18 GHz range, and being able to shield by absorption. The material is the best of our knowledge this specific SE value appears to be the highest reported hitherto. Improved EM absorbers should fulfil the synergic requirements of being low reflective and highly absorptive. In our CNT‐sponges this condition is not satisfied because, although their net absorption ability is strongly remarkable, their high electrical conductivity favours the wave to be reflected at the input interface. Therefore, this sponge material would have a great potential for microwave‐frequency applications that need negligible reflection and great absorption when combined in a multilayered structure that could prevent the wave to be reflected at the input interface. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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The influence of single-walled carbon nanotube structure on the electromagnetic interference shielding efficiency of its epoxy composites

Cited by 530 publications

References 31 publications

Conjugated polymer nanocomposites: Synthesis, dielectric, and microwave absorption studies

Conjugated polymer nanocomposites: Synthesis, dielectric, and microwave absorption studies

Low electrical percolation threshold and PL quenching in solution-blended MWNT–MEH PPV nanocomposites

Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range

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