Electromagnetic (EM) pollution affecting people's normal lives and health has attracted considerable attention in the current society. In this work, a promising EM wave absorption and shielding material, MXene/Ni hybrid, composed of one-dimensional Ni nanochains and two-dimensional Ti3C2Tx nanosheets (MXene), is successfully designed and developed. As expected, excellent EM wave absorption and shielding properties are obtained and controlled by only adjusting the MXene content in the hybrid. A minimum reflection loss of -49.9 dB is obtained only with a thickness of 1.75 mm at 11.9 GHz when the MXene content is 10 wt %. Upon further increasing the MXene content to 50 wt %, the optimal EM shielding effectiveness (SE) reaches 66.4 dB with an absorption effectiveness (SEA) of 59.9 dB. Mechanism analysis reveals that the excellent EM wave absorption and shielding performances of the hybrid are contributed to the synergistic effect of conductive MXene and magnetic Ni chains, by which, the dielectric properties and electromagnetic loss can be easily controlled to obtain appropriate impedance matching conditions and good EM wave dissipation ability. This work provides a simple but effective route to develop MXene-based EM wave absorption and shielding materials. A universal guideline for designing the absorbing and shielding materials for the future is also proposed.

Promising Ti3C2Tx MXene/Ni Chain Hybrid with Excellent Electromagnetic Wave Absorption and Shielding Capacity.

In this study, we fabricated conductive poly(vinylidene fluoride) (PVDF)/carbon composites simply by dispersing multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets into a PVDF solution The electrical conductivity and the electromagnetic interference (EMI) shielding of the PVDF/carbon composites were increased by increasing the conductive carbon filler amounts Moreover, we also found that the EMI shielding properties of the PVDF/CNT/graphene composites were higher than those of PVDF/CNT and PVDF/graphene composites The mean EMI shielding values of PVDF/5 wt %-CNT, PVDF/10 wt %-graphene, and PVDF/CNT/graphene composite films with a thickness of 01 mm were 2241, 1870, and 2758 dB, respectively An analysis of the shielding mechanism showed that the main contribution to the EMI shielding came from the absorption mechanism, and that the EMI shielding could be tuned by controlling the films’ thickness The total shielding of the PVDF/CNT/graphene films increased from 2190 to 3646 dB as the

Flexible, Ultrathin, and High-Efficiency Electromagnetic Shielding Properties of Poly(Vinylidene Fluoride)/Carbon Composite Films.

MXenes, new two-dimensional compounds with hydrophilic surfaces and high metallic conductivity, have attracted significant interest in the electromagnetic interference shielding field in recent years. Nevertheless, poor mechanical properties and brittle nature are bottlenecks for their commercial application. Herein, one-dimensional ANFs were designed as the intermolecular cross-linker between d-Ti3C2Tx flakes and MXene (d-Ti3C2Tx)/aramid nanofiber (ANF) composite paper with a multi-layered structure was fabricated via the vacuum-assisted filtration approach. Further investigation revealed that the ANFs and MXene displayed good combination by hydrogen bonding, and MXene/ANF composite papers exhibited excellent mechanical properties and superior electrical conductivity. The MXene/ANF composite paper possessed a favorable shielding effectiveness (SE) which reached ∼28 dB in 8.2-12.4 GHz (X band) with an ultra-thin thickness ∼17 μm and showed potential application prospects as an advanced composite in sensitive electronic products.

Ultrathin MXene/aramid nanofiber composite paper with excellent mechanical properties for efficient electromagnetic interference shielding

To minimize electromagnetic (EM) pollution, two key parameters, namely, intrinsic wave impedance matching and intense absorption of incoming EM radiation, must satisfy the utmost requirements. To target these requirements, soft conducting composites consisting of binary blends of polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) were designed with doped multiwalled carbon nanotubes (MWCNTs) and a three-dimensional cross-linked graphene oxide (GO) framework doped with ferrite nanoparticles. The doping of α-MnO2 onto the MWCNTs ensured intrinsic wave impedance matching in addition to providing conducting pathways, and the ferrite-doped cross-linked GO facilitated the enhanced attenuation of the incoming EM radiation. This unique combination of magnetodielectric coupling led to a very high electromagnetic shielding efficiency (SE) of −37 dB at 18 GHz, dominated by absorption-driven shielding. The promising results from the composites further motivated us to rationally stack individual composites into a...

Absorption-Dominated Electromagnetic Wave Suppressor Derived from Ferrite-Doped Cross-Linked Graphene Framework and Conducting Carbon

We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings (FeNR@rGO) by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO:α-Fe2O3 mass ratio of 1:1 prepared by annealing in H2/Ar for 3 h exhibited the best properties. This nanocomposite sample (thickness = 4.0 mm) showed a minimum reflectivity of–23.09 dB at 9.16 GHz. The band range was 7.4–11.3 GHz when the reflectivity was less than–10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.

Electromagnetic wave absorption in reduced graphene oxide functionalized with Fe 3 O 4 /Fe nanorings

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.

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 2.70 S/cm at 1 MHz. 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 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt. % graphite in PVDF.

R. Kumaran

Papers

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

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