Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Abstract

In this study, a novel composite of Fe3O4 nanofiller-decorated single-layer graphene-assembled porous carbon (SLGAPC) with polyvinyl alcohol (PVA) having flexibility and a density of 0.75 g cm(-3) is explored for its dielectric and electromagnetic interference (EMI) response properties. The composite is prepared by the solution casting method and its constituents are optimized as 15 wt% SLGAPC and 20 wt% Fe3O4 through a novel solvent relaxation nuclear magnetic resonance experiment. The PVA-SLGAPC-Fe3O4 composite shows high dielectric permittivity in the range of 1 Hz-10 MHz, enhanced by a factor of 4 as compared to that of the PVA-SLGAPC composite, with a reduced loss by a factor of 2. The temperature dependent dielectric properties reveal the activation energy behaviour with reference to the glass transition temperature (80 °C) of PVA. The dielectric hysteresis with the temperature cycle reveals a remnant polarization. The enhanced dielectric properties are suggested to be the result of improvement in the localized polarization of the integrated interface system (Maxwell-Wagner-Sillars (MWS) polarization) formed by the uniform adsorption of Fe3O4 on the surface of SLGAPC conjugated with PVA. The EMI shielding property of the composite with a low thickness of 0.3 mm in the X-band (8.2-12.4 GHz) shows a very impressive shielding efficiency of ∼15 dB and a specific shielding effectiveness of 20 dB (g cm(-3))(-1), indicating the promising character of this material for flexible EMI shielding applications.

Ice-templated synthesis of multifunctional three dimensional graphene/noble metal nanocomposites and their mechanical, electrical, catalytic and electromagnetic shielding properties

“…The total SE by the absorption phenomenon is mainly due to the interaction of electric dipoles with the electromagnetic field of radiation and the functional groups of functionalized 3D-graphene attained by the addition of noble metal (Pt, Ag) particles. Thus, the incorporation of fillers in the 3D-graphene plays an important role for improving the structure and electrical conductivity, which also revealed by our earlier study 54 . The dispersion of particles on the surface of the 3D building-block nanosheets was uniform and reduced the skin depth by improving the absorption losses, resulting in a higher surface; this further enhances the SE.…”

Graphene and Iron Reinforced Polymer Composite Electromagnetic Shielding Applications: A Review

“…Rao et al [ 163 ] synthesized Fe 3 O 4 with single-layer graphene-assembled porous carbon (SLGAPC) and polyvinyl alcohol (PVA) via the solution casting method. With a thickness of 0.3 mm, the shielding effectiveness of 20 dB was achieved in the X-band frequency range.…”

Microneedles of chitosan‐porous carbon nanocomposites: Stimuli (pH and electric field)‐initiated drug delivery and toxicological studies

“…Hence to extract measurable inferences from the skin is quite challenging. 43 Therefore, it was more convenient to compare conductivity at 1 KHz frequency for electric field tuning drug delivery application. 32 In our case, we are using 100 non-hallow MNs array with the area 0.25 cm 2 , which undergo the applied stress up to MNs breaking point by varying different concentration of GAPC into CS-CPL nanocomposite.…”

“…When comparing the conductivity values at 1 kHz for composite films, it was seen that the conductivity increased steeply with addition of 1% GAPC in CS and CS-CPL MNs. 43 Therefore, it was more convenient to compare conductivity at 1 KHz frequency for electric field tuning drug delivery application. In conclusion, results show that conductivity increases upon addition of GAPC into CS nanocomposite.…”