Nanoscaled self-alignment of Fe₃O₄nanodiscs in ultrathin rGO films with engineered conductivity for electromagnetic interference shielding

Abstract

Ultrathin (∼2 μm) reduced graphene oxide (rGO) film embedded with self-aligned Fe3O4 nanodiscs were successfully fabricated through the filtration-assisted self-assembly method. In the as-fabricated hybrid film, Fe3O4 nanodiscs with thin thickness (26 nm) and high aspect ratio (∼9) were readily self-assembled and aligned in rGO intersheets under the assistance of hydrostatic forces. Compared with spherical Fe3O4 nanoparticles, introducing the Fe3O4 nanodiscs into rGO paper could not only offer high magnetic permeability and magnetic loss in a broad frequency range at the gigahertz level, but also increase the electrical conductivity of rGO film by means of improving the surface roughness without disrupting the conductive network of the rGO layers. Due to the above advantages, the free-standing rGO/Fe3O4 nanodisc magnetic hybrid film (56 wt%) exhibited an EMI shielding effectiveness (SE) of around 11.2 dB in the frequency range of 2-10 GHz, which is about 50% and 72% higher than that of neat rGO film and rGO/Fe3O4 nanosphere hybrid films (with similar particle size and loading weight fraction) prepared under the same conditions, respectively. Furthermore, compared with non-magnetic neat rGO film, the outstanding magnetic properties of the rGO/Fe3O4 nanodisc film paves the way for it to be used as a multifunctional material that can be controlled by magnetic fields. Additionally, the moderate thermal reduction temperature (420 °C) would be meaningful for large scale fabrication. Meanwhile, the strategy of achieving good alignment at the nanoscale could shed light on developing heterogeneous structures with self-aligned two-dimensional (2D) (magnetic or non-magnetic) nano-inclusions for various applications.

An Experimental Study on Static and Dynamic Strain Sensitivity of Embeddable Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

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Polymeric nanocomposites reinforced with nanowires: Opening doors to future applications

“…Electromagnetic interference (EMI) pollution has been known to cause unforeseen damage to human health and electronic device operation. 83,84 Consequently, abolition of potentially harmful electromagnetic radiations has been discussed especially for developing EMI shielding materials. 85,86 Intrinsically conducting polymers such as PANI, PPy, polythiophene and their conducting nanocomposites have been employed as essential EMI shielding materials.…”

Electrical, Dielectric and Magnetic Properties of Mg2+ Doped Zn-Co-La Spinel Ferrites for High Microwave Frequency (5.7-13.4 GHz) Applications

“…Size, shape, purity and magnetic stability of the ultrafine powder consisting of ferrite nanomaterials depends upon the processing conditions and synthesis method [2][3]. These soft ferrites can be used in different applications like magneto optical recording media and pulse power by varying the different parameters like low temperature annealing, doping, sintering at high temperature [4][5][6][7][8][9]. Ferrites retain the properties like lower dielectric fatalities, higher resistivity, larger Curie temperature, abatement cost and high macerating magnetization.…”