Suppressing Electromagnetic Radiation by Trapping Ferrite Nanoparticles and Carbon Nanotubes in Hierarchical Nanoporous Structures Designed by Crystallization‐Induced Phase Separation

Sharma, Maya; Singh, Deepinder; Menon, Aishwarya V.; Madras, Giridhar; Bose, Suryasarathi

doi:10.1002/slct.201702731

Cited by 23 publications

(9 citation statements)

References 51 publications

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“…The contribution of shielding effectiveness via absorption is found to be greater than the contribution of reflection in total shielding effectiveness. The total shielding effectiveness for all the samples is quite higher than the value required industrial application (∼30 dB) and various reports available on composites of polyaniline and other carbon structures . For example, Chaudhary et al .…”

Section: Resultsmentioning

confidence: 76%

“…The electromagnetic interference shielding effectiveness (EMI‐SE) of a barrier material is the measure of the attenuation in the electromagnetic field strength at any point in space on the insertion of a shielding material, so‐called attenuation of electromagnetic wave and measured in decibel (dB). It is generally defined as the ratio of field strength of the incident radiation to the field strength of the transmitted radiation and can be expressed as

true S E = 10 l o g \frac{P_{i}}{P_{T}} = 20 l o g \frac{H_{i}}{H_{T}} = 20 l o g \frac{E_{i}}{E_{T}}

…”

Section: Resultsmentioning

confidence: 99%

“…Since, polymers are lightweight but electrically insulator and non‐magnetic in nature, therefore, transparent to EM waves. Thus, electrical and magnetic dipoles are introduced by incorporating various kinds of magnetic particles including iron, nickel and cobalt, etc., or by electrically conducting fillers like carbon nanotubes, etc . These materials not only enhanced electrical conductivity but also reinforced the structural conformation because of their high aspect ratio.…”

Section: Resultsmentioning

confidence: 99%

“…However, it is difficult to measure the shielding effectiveness directly for a barrier materials and therefore, the scattering parameters {S ij (i=1,2; j=1,2)} such as S11, S22, S12 and S21 of the EM wave are measured with the help of vector network analyzer (VNA), where, these scattering parameters S11 (or S22) and S12 (or S21) are associated with the amount of refection and transmission of electromagnetic wave, respectively. The reflectance (R) and transmittance (T) of the electromagnetic wave through the barrier can be calculated using these parameters as follows

true R = {((), \frac{P_{r}}{P_{i}})}^{2} = {(||, S_{11}, o, r, S_{22})}^{2}

true normalT = {((), \frac{P_{T}}{P_{i}})}^{2} = {(||, {normalS}_{12}, o, r, {normalS}_{21})}^{2}

…”

Section: Resultsmentioning

confidence: 99%

“…where, P i , P r , and P T are the incident, reflected and transmitted powers of EM wave, respectively and the shielding effectiveness by absorption (SEa) and reflection (SEr) can be calculated using the scattering parameters using the relations

true {normalS normalE}_{r} = 10 \log ((), \frac{1}{1 - {|S_{11}|}^{2}}) = 10 \log ((), \frac{1}{1 - R}) = - 10 normall normalo normalg (1 - R)

true {normalS normalE}_{a} = 10 \log ((), \frac{1 - {|S_{11}|}^{2}}{{(||, {normalS}_{12})}^{2}}) = 10 \log ((), \frac{1 - R}{normalT}) = - 10 \log ((), \frac{normalT}{1 - R})

true {normalS normalE}_{T} = 10 \log ((), \frac{1}{{(||, {normalS}_{12})}^{2}}) = 10 \log ((), \frac{1}{normalT}) = - 10 \log ((), T)

…”

Section: Resultsmentioning

confidence: 99%

See 4 more Smart Citations

MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

et al. 2019

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The core-shell structured based Polyaniline/MnO 2 composites were synthesized by chemical oxidation method, wherein MnO 2 particles acts as a magnetic core while polyaniline chains wrapped over these particles acts as a shell. Four different loading concentrations of MnO 2 particles (10, 20, 30 and 40 wt %) were used to investigate the effect of MnO 2 concentration on the EMI shielding effectiveness. X-ray diffraction (XRD) studies performed on pristine MnO 2 and composite samples reveal the polycrystalline nature of the MnO 2 particles and semi-crystalline nature of the composites with a sharp peak around 25°over a broad hump. Vibrating sample magnetometry (VSM) studies performed on the pristine MnO 2 particles as well composite sample (S4) at higher loading (40 wt %) concentration of MnO 2 suggest the ferromagnetic nature at room temperature. The charge transport properties of the prepared samples have been investigated under variable range hopping (VRH) conduction. Mott's three dimensional VRH model has been found to be applicable for conduction in the present samples. The dc conductivity of the prepared samples is found to increase with MnO 2 loading concentrations, which suggest their possible validity for EMI shielding applications. Therefore, the prepared samples are analyzed for EMI shielding properties in the frequency range of 8.2 to 12.4 GHz (X-band). The sample prepared with 30 wt% of MnO 2 has as much as 50 dB shielding effectiveness, which is quite higher than that required for industrial application (∼ 30dB).[a] R. Pal, Prof.

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Section: Resultsmentioning

confidence: 76%

true S E = 10 l o g \frac{P_{i}}{P_{T}} = 20 l o g \frac{H_{i}}{H_{T}} = 20 l o g \frac{E_{i}}{E_{T}}

…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

true R = {((), \frac{P_{r}}{P_{i}})}^{2} = {(||, S_{11}, o, r, S_{22})}^{2}

true normalT = {((), \frac{P_{T}}{P_{i}})}^{2} = {(||, {normalS}_{12}, o, r, {normalS}_{21})}^{2}

…”

Section: Resultsmentioning

confidence: 99%

true {normalS normalE}_{r} = 10 \log ((), \frac{1}{1 - {|S_{11}|}^{2}}) = 10 \log ((), \frac{1}{1 - R}) = - 10 normall normalo normalg (1 - R)

true {normalS normalE}_{a} = 10 \log ((), \frac{1 - {|S_{11}|}^{2}}{{(||, {normalS}_{12})}^{2}}) = 10 \log ((), \frac{1 - R}{normalT}) = - 10 \log ((), \frac{normalT}{1 - R})

true {normalS normalE}_{T} = 10 \log ((), \frac{1}{{(||, {normalS}_{12})}^{2}}) = 10 \log ((), \frac{1}{normalT}) = - 10 \log ((), T)

…”

Section: Resultsmentioning

confidence: 99%

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MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

et al. 2019

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Simultaneous Construct Surface Microstructural and Internal Network‐Like Conductive Pathways of Poly(l‐lactic acid)/Carbon Nanomaterials Composite Foams

Sun

Guo

Yang

et al. 2023

Macro Chemistry & Physics

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The poly(l-lactic acid) (PLLA)/carbon nanomaterials composite foams with hierarchical surface microstructural and internal conductive pathways are successfully prepared by a simple crystallization-assisted rapid phase separation (CARPS). The dimension and morphology of carbon nanomaterials can induce different crystallization forms to construct the hierarchical surface microstructure, and they are distributed on the phase interface of solvent and non-solvent to form conductive pathways. It is found that the heterogeneous nucleation of nanomaterials promotes a significant increase in crystallinity, and a stacked granular structure formed on the surface promotes the increase of the water contact angle to 148.7°. Foams with interconnecting pore structures contribute to the formation of 85.3% porosity and 12.33 g g −1 oil absorption. Carbon nanomaterials are distributed on the pore walls of the porous foam, which converts the foam from an insulating material to a conducting polymer. Furthermore, the uniform distribution of nanomaterials significantly affects the thermal stability of the PLLA. In belief, the multifunctional biodegradable foam, prepared by a CARPS method, makes it promising for industrial production and has potential applications in electrical conductivity, oil-water separation, and many other fields.

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Electromagnetic interference shielding performance of in-situ polymerized PANI/Fe3O4 nanocomposites in X-band frequency range

Ruchi,

Gupta,

Dalal

et al. 2023

Polym. Bull.

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Suppressing Electromagnetic Radiation by Trapping Ferrite Nanoparticles and Carbon Nanotubes in Hierarchical Nanoporous Structures Designed by Crystallization‐Induced Phase Separation

Cited by 23 publications

References 51 publications

MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

Simultaneous Construct Surface Microstructural and Internal Network‐Like Conductive Pathways of Poly(l‐lactic acid)/Carbon Nanomaterials Composite Foams

Electromagnetic interference shielding performance of in-situ polymerized PANI/Fe3O4 nanocomposites in X-band frequency range

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Suppressing Electromagnetic Radiation by Trapping Ferrite Nanoparticles and Carbon Nanotubes in Hierarchical Nanoporous Structures Designed by Crystallization‐Induced Phase Separation

Cited by 23 publications

References 51 publications

MnO2‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

MnO2‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

Simultaneous Construct Surface Microstructural and Internal Network‐Like Conductive Pathways of Poly(l‐lactic acid)/Carbon Nanomaterials Composite Foams

Electromagnetic interference shielding performance of in-situ polymerized PANI/Fe3O4 nanocomposites in X-band frequency range

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Product

Resources

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MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction

MnO₂‐Magnetic Core‐Shell Structured Polyaniline Dependent Enhanced EMI Shielding Effectiveness: A Study of VRH Conduction