Co/Co₃O₄ Based Nanoparticles and Their Polymer Composites for Tuned Electromagnetic Interference Shielding Application

Abstract

The magnetic properties of the metal nanoparticles (NPs) can play remarkable role in electromagnetic interference shielding (EMI Shielding) of many defence and commercial electronic devices. In the present work, coconut oil and PVA capped magnetic cobalt/cobalt oxide nanoparticles (Co/Co3O4 NPs) were synthesized by chemical reduction method and impregnated in polymer matrix to verify their EMI shielding behaviour. The coconut oil capped Co/Co3O4 NPs with presence of hcp and fcc phases were prepared in the size domain of 7–10 nm and the effect of surfactant (the oil) on size and oxidation state was studied by varying the ratios. The shielding efficiencies of Co/Co3O4 NPs PVA nanocomposites were analysed by using vector network analyser (VNA) in X- and Ku-band ranging from 8 GHz–18 GHz. The VNA results showed increased shielding efficiency with increasing concentration of NPs.

A multi-functional porous cobalt catalyst for the selective hydrogenative ring-opening and rearrangement of furfural to cyclopentanol

“…This may be due to the possible low-intensity absorption of amorphous Co 3 O 4 in visible light. 20 This result was consistent with the XRD pattern (Fig. 1).…”

Recent advancements in the electromagnetic interference shielding performance of nanostructured materials and their nanocomposites: a review

“…PEDOT–RGO–Co 3 O 4 (thickness: 2.0 mm) also showed maximum R L up to −51.1 dB at 10.7 GHz and the bandwidth exceeding −10 D was 3.1 GHz. PANI/RGO/Co 3 O 4 (2–4 mm, 2–18 GHz), 339 Co/Co 3 O 4 -based composites, 340 hetero-nanostructured Co@CNT-graphene ternary hybrids, 341 flake-shaped graphene nanofiber/PPy/Fe 3 O 4 (2% loading) on non-polar plastic, 342 and FeCo@SnO 2 @GN@PANI in paraffin 343 also exhibited excellent microwave absorption properties.…”

“…The microwave absorption performance of RGO/ Fe 3 O 4 /PANI was found up to À28.2 dB (14.4 GHz) and the absorption bandwidth below À10 dB to be 5.4 GHz (from 12.6 to 18 GHz) with a thickness of 2 mm. 327 Manna and Srivastava 340 hetero-nanostructured Co@CNT-graphene ternary hybrids, 341 ake-shaped graphene nanober/PPy/Fe 3 O 4 (2% loading) on non-polar plastic, 342 and FeCo@SnO 2 @GN@PANI in paraffin 343 also exhibited excellent microwave absorption properties.…”

“…Studies were conducted on several nanomaterials, such as ferromagnetic element nanoalloys, metal oxides, ferrites and their polymers and ICP-based nanocomposites in EMI shielding applications. 276–405 The choice of magnetic materials-filled ICP nanocomposites in EMI shielding applications is mainly guided by the dielectric loss, magnetic loss and impedance matching of the component(s) of the material(s) under investigation. It provides a combination of magnetic nanoparticles and ICPs that account for its additionally reduced weight, cost, enhanced flexibility and corrosion resistance, tuneability conductivity and tailorable permeability.…”

Ultra-flexible trilaminar aramid fiber based ANF(Ag/Fe3O4-CNT/rGO) hybrid membrane for high- performance electromagnetic interference shielding

“…Among them, aramid nano ber ber (ANF) has a negative surface charge, easily forming a strong binding force with other nanocomposites. Generally, conductive particles (e.g., silver nanowire [20][21][22], graphene [23,24], carbon nanotube [25,26] and MXene [27,28]) or magnetic particles (e.g., cobalt oxide [29,30], iron oxide [31,32]) are mechanically mixed with polymers to build a conductive network or magnetic layer in the polymer matrix to achieve satisfactory EMI shielding performance. For instance, Hu et al [33] successfully prepared lightweight, highly conductive and hydrophobic ANF/CNT aerogel lms by deprotonation, freeze drying and uorocarbon resin coating, which exhibited superior electrical conductivity of 230 S/m, EMI SE of > 54 dB over the X-band at the thickness of 568 µm and water contact angle of 137.0°.…”