Multi-walled carbon nanotube–graphene–polyaniline multiphase nanocomposite with superior electromagnetic shielding effectiveness

Gupta, Tejendra K.; Singh, Bhanu Pratap; Mathur, R.B.; Dhakate, Sanjay R.

doi:10.1039/c3nr04565j

Cited by 298 publications

(127 citation statements)

References 57 publications

(46 reference statements)

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“…5(a) that 3 0 shows the highest value of 335 at 12.7 GHz and it decreases with uc-tuations (from 320 to 223) in the 12.4-18.0 GHz range, similar to earlier reports. 36,43,44 The 3 00 value is lower than 3 0 and it uctuates (from 173 to 100) in the 12.4-18.0 GHz range. The relatively high values of 3 00 and tan d 3 ( Fig.…”

Section: Microwave Shielding Effectivenessmentioning

confidence: 99%

MnO2 decorated graphene nanoribbons with superior permittivity and excellent microwave shielding properties

Gupta

Singh

Singh³

et al. 2014

J. Mater. Chem. A

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221

106

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Microwave shielding properties of chemically synthesized MnO 2 decorated graphene nanoribbons (GNRs) are reported for the first time. The nature of MnO 2 decoration on the GNRs has been investigated using scanning electron microscopy, X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. The electromagnetic interference (EMI) shielding effectiveness of this material was investigated in the microwave region . The presence of MnO 2 on GNR enhances the interfacial polarization, multiple scattering, natural resonances and the effective anisotropy energy, which leads to absorption dominated high shielding effectiveness of À57 dB (blocking >99.9999% radiation) by a 3 mm thick sample. Dielectric attributes (3 0 and 3 00 ) were evaluated to understand the mechanism of the excellent shielding effectiveness. The material will be an excellent choice for radar absorbing applications.

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Section: Microwave Shielding Effectivenessmentioning

confidence: 99%

MnO2 decorated graphene nanoribbons with superior permittivity and excellent microwave shielding properties

Gupta

Singh

Singh³

et al. 2014

J. Mater. Chem. A

Self Cite

221

106

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“…As produced MWCNT was functionalized by reuxing in nitric acid for 48 h (ref. [29][30][31]) and designated as a-MWCNT.…”

Section: Methodsmentioning

confidence: 99%

Depression in glass transition temperature of multiwalled carbon nanotubes reinforced polycarbonate composites: effect of functionalization

et al. 2015

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Functionalized multiwalled carbon nanotubes (a-MWCNTs) and non-functionalized MWCNTs were melt mixed with polycarbonate polymer by utilizing twin screw micro compounder having a back flow channel to obtain nanocomposites with varying composition from 0.5 to 10 wt% MWCNT and 2 wt% a-MWCNT. Mechanical properties of composite samples were studied using dynamic mechanical analyzer, flexural and tensile tests. Both DMA and flexural and tensile tests suggest formation of continuous network of CNT-polymer that is supported by measured storage modulus for different loading of MWCNT and a-MWCNT. The composite sample showed lower glass transition temperature (T g ) as compared to pure PC. Effect of functionalization of MWCNTs on T g of its of polycarbonate composites is studied and showed higher T g depression in functionalized MWCNTs compared to non functionalized MWCNTs based composites over pure polycarbonate. In DMA, lowering of height of tan delta peak indicates that polymer in composite material participating in T g was reduced along with loading of MWCNT, consistent with immobilization of polymer material present at the CNT interface.Effect of functionalization on morphology was investigated using scanning electron microscope and confirms the better interaction in case of a-MWCNTs compare to MWCNTs based composites. Further, Raman spectroscopic analysis indicates higher interaction between a-MWCNT and PC matrix as compared to as synthesized MWCNT.

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“…The resulting solution was dried and few layer graphene (FLG) nano sheets (GNS) in the form of powder were obtained. 80 The FLG nano sheets derived from the ball milling of expanded graphite in organic solvent was used as conducting reinforcement in the pre-synthesized precursor of Mg 3 Sb 2 . Before mixing of graphene in Mg 3 Sb 2 matrix, it was ball milled for two hours to disperse the GNS properly.…”

Section: Introductionmentioning

confidence: 99%

Graphene boosts thermoelectric performance of a Zintl phase compound

et al. 2015

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The concept of nanocomposites derived by incorporating a second minor phase in bulk thermoelectric materials has established itself as an effective paradigm for optimizing high thermoelectric performance.In this work, this paradigm is for the first time extended to bulk Zintl phase Mg 3 Sb 2 and its isoelectronically Bi-doped derivative Mg 3 Sb 1.8 Bi 0.2 system. Herein, we report the synthesis, microstructural details, electronic structure and thermoelectric properties of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/ graphene nanosheet (GNS) nanocomposites with different mass ratios. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigation reveals that Mg 3 Sb 2 nanoparticles are homogenously anchored on the surface of GNS. We demonstrate that Mg 3 Sb 2 -based materials incorporated with a small content of graphene outperform optimally, resulting in potential ptype thermoelectric materials. The present nanocomposite additive of GNS deriving such a novel nanocomposite of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/GNS, enhances the electrical conductivity significantly, thereby resulting in a substantially large increase in the power factor. The enhanced electrical conductivity of these nanocomposites is attributed to the increase in the carrier concentration and high carrier mobility owing to the ultra high mobility of graphene. X-ray photoelectron spectroscopy (XPS) core level spectra confirm weak bonding between GNS and Mg 3 Sb 2 . Increase in carrier concentration is reflected in XPS valence band spectra and change in spectral weight near valence band maxima is indicative of increased electrical conductivity in the nanocomposite material. The thermal conductivity of these nanocomposites is noted to be reduced at high temperature. These favorable conditions lead to enhanced thermoelectric figure-of-merit (ZT) z 0.71 at 773 K for Mg 3 Sb 2 /GNS and a ZT z 1.35 at 773 K for Mg 3 Sb 1.8 Bi 0.2 /GNS nanocomposites with the mass ratio of 80 : 1 which are $170% and $125% higher values compared to bare Mg 3 Sb 2 and bare Mg 3 Sb 1.8 Bi 0.2 respectively. We strongly believe that the present novel strategy of fabricating such a nanocomposite of a Zintl compound by utilizing GNS as a nanocomposite additive, may provide an emerging path for improving thermoelectric properties of various Zintl phase compounds.

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Multi-walled carbon nanotube–graphene–polyaniline multiphase nanocomposite with superior electromagnetic shielding effectiveness

Cited by 298 publications

References 57 publications

MnO2 decorated graphene nanoribbons with superior permittivity and excellent microwave shielding properties

MnO2 decorated graphene nanoribbons with superior permittivity and excellent microwave shielding properties

Depression in glass transition temperature of multiwalled carbon nanotubes reinforced polycarbonate composites: effect of functionalization

Graphene boosts thermoelectric performance of a Zintl phase compound

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