Composites of polyvinylidene fluoride (PVDF) with micron and nano sized BaTiO3 powders were developed for electromagnetic interference (EMI) shielding applications in the X band. PVDF-nano BaTiO3 composites show better shielding property compared to PVDF-micron sized BaTiO3 composites. The composite of PVDF with 40 vol% of nano BaTiO3 showed the best EMI shielding effectiveness and is about 9 dB. The contributions from reflection and absorption to the total EMI shielding effectiveness is same for the PVDF-BaTiO3 composites. Addition of small amount of silver particles improved the shielding properties of these composites due to the increased conductivity. An EMI shielding effectiveness of about 26 dB is obtained in the measured frequency range for the PVDF-20 vol% nano BaTiO 3-10 vol% Ag composite of thickness 1.2 mm. Novel three phase composite combining the advantages of metal, nano ceramic and polymer is obtained with the potential for effective EMI shielding applications. © 2013 Elsevier Ltd.

Vemuri Rama Krishna Murthy

A. Ceramics

BATIO

EFFECT OF SILVERS

EMI SHIELDING

EMI SHIELDING EFFECTIVENESS

Frequency ranges

NANO CERAMICS

Nano sized

NANO-BATIO

Polyvinylidene fluorides

SHIELDING APPLICATIONS

SHIELDING PROPERTIES

SILVER PARTICLES

THREE-PHASE COMPOSITES

X bands

Barium titanate

Ceramic materials

Electromagnetic pulse

Magnetic shielding

Silver

Dielectric properties of solids

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Research Bulletin

Electromagnetic interference (EMI) shielding effectiveness and conductivities in a flexible conducting polymer composite film, prepared via a simple solvent cast method, of PVDF incorporated with Au-MWCNT are studied. The scanning electron microscopic analysis showed that the Au-loaded MWCNT uniformly dispersed in PVDF. The HRTEM images show that Au nanoparticles having a particle size of 20-30 nm have been deposited on the nodes of the MWCNT. The values of dielectric constant were found to be 12.11 and 13.89 at 1 MHz upon the incorporation of 1 and 3 wt % MWCNT in PVDF. The impedance and electromagnetic interference shielding effectiveness studies reveal that the polymer nanocomposites possess enhanced conductivity of 1.12 × 10-4 S/cm at 1 MHz, minimum return loss of 4.4 dB, and effective electromagnetic shielding of 26.7 dB at 12 GHz for 3 wt % Au NPs in 3 wt % MWCNT/PVDF thin film. © 2016 American Chemical Society.

Journal of Physical Chemistry C

Enhanced Electromagnetic Interference Shielding in a Au-MWCNT Composite Nanostructure Dispersed PVDF Thin Films

We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70S/cm at 1MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1dB at 12.4GHz for the sample having 5wt.% Ag and 10wt.% graphite in PVDF. © 2015 AIP Publishing LLC.

Fulltext

Applied Physics Letters

Ag induced electromagnetic interference shielding of Ag-graphite/PVDF flexible nanocomposites thinfilms

Microwave processed Ni1-xMgxFe2O4 with x = 0.0–1.0 are characterized fordc,ac conductivities and dielectric properties as a function of temperature and frequency. Very low dielectric loss tangent is achieved at 5 MHz frequency. Grain and grain boundary contribution towards conductivity is presented on the basis of Nyquist plots and their resistances are evaluated from semi-circular arcs. Equivalent electrical circuits and approximate R-C values are presented for better insight. High dielectric constant of 41 for x = 0.8 sample instigated the possibility of good electromagnetic absorption material. A shift in the transport phenomenon is suggested from band like to polaron hopping with rise in temperature.In addition the electromagnetic interference shielding properties are studied in X-band.The results show that the goodelectromagnetic interference shielding efficiency is achieved for x = 0.4 − 0.6 compositions ranging from 10 to 17 dB (at 8.4 GHz) which is suitable for shielding application. © 2017 Elsevier Ltd

Investigations on transport, impedance and electromagnetic interference shielding properties of microwave processed NiMg ferrites

Ni0.2Mg0.8-xZnxFe2O4 (x = 0.2 , 0.4, 0.6, and 0.8) ferrites are synthesized via microwave solid-state reaction method. The diffraction study confirms the cubic spinel structure of samples. The fracture surface is analyzed by scanning electron microscope. In addition, the X-band (8.4-12 GHz) electromagnetic interference (EMI) properties are investigated. The NiMgZn ferrite system attributes the total EMI shielding effectiveness (SET) altering between 9 and 12 dB, which provides the electromagnetic shielding applications. The variation of electromagnetic parameters such as dielectric constant (g'

IEEE Transactions on Magnetics

Microwave Processed NiMgZn Ferrites for Electromagnetic Intereference Shielding Applications

A new anti-reflection coating based on amorphous barium titanate (a-BTO) was developed using RF magnetron sputtering technique. Systematic studies on the structural and optical properties were carried on a-BTO thin films deposited on polished Si and textured Si substrates. In the visible range of the solar spectrum, the refractive index was found to be 2.02-1.91 with high transmittance of greater than 85%. Maximum reduction in the reflectance for a-BTO on polished Si and textured Si substrates was found to be 100% (at 550 nm) and 85% (at 400 nm), respectively. Further, improvement in cell efficiency of a Si solar cell with a-BTO anti-reflection coating was found with an increase from 9.3% to 10% accompanied by improvements in overall performance parameters such as short circuit density (Jsc), open circuit voltage (Voc) and fill factor (FF). These results indicate that an a-BTO thin film deposited using RF magnetron sputtering can be used as an alternative anti-reflection coating for Si based photovoltaic cells. © The Royal Society of Chemistry 2015.

RSC Advances

An amorphous barium titanate thin film improves light trapping in Si solar cells

Novel polymer nanocomposites comprising of MnO2 nanotubes (MNTs), functionalized multiwalled carbon nanotubes (f-MWCNTs), and polyvinylidene fluoride (PVDF) were synthesized. Homogeneous distribution of f- MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy. Electrical conductivity measurements were performed on these polymer composites using four probe technique. The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m). Electromagnetic interference shielding effectiveness (EMI SE) was measured with vector network analyzer using waveguide sample holder in X-band frequency range. EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region. © 2011 Eswaraiah et al.

Nanoscale Research Letters

Inorganic nanotubes reinforced polyvinylidene fluoride composites as low-cost electromagnetic interference shielding materials

Journal of Materials Science

Electrical conductivity and shielding effectiveness of poly(trimethylene terephthalate)/multiwalled carbon nanotube composites

Journal of Materials Science: Materials in Electronics

Reaction kinetic, magnetic and microwave absorption studies of SrFe11.2Ni 0.8O19 hexaferrite nanoparticles

Acta Materialia

Multifunctional hybrids for electromagnetic absorption

Journal of Magnetism and Magnetic Materials

Optimization of electromagnetic matching of carbonyl iron/BaTiO3 composites for microwave absorption

Effect of silver incorporation into PVDF-barium titanate composites for EMI shielding applications

Journal	Materials Research Bulletin
ISSN	00255408
Open Access	No