Enhanced Electromagnetic Absorption Properties of Commercial Ni/MWCNTs Composites by Adjusting Dielectric Properties

Abstract

In this manuscript, we constructed a Ni/MWCNTs absorber and properly adjusted the permittivity resulted from absorber content in the PVDF to optimize impedance matching properties. Both ε ′ and ε ′′ increase obviously with the increasing content of Ni/MWCNTs in PVDF, demonstrating that dielectric properties are dependent on the conductivity. Moderate dielectric properties and excellent impedance matching can be obtained for the filler content of 20 wt% Ni/MWCNTs. Reasonable impedance matching allows electromagnetic waves to propagate into the materials and finally realize energy dissipation through dielectric loss and interfacial polarization. As expected, the minimum reflection loss (RL) of −46.85 dB at 6.56 GHz with a low filler loading (20 wt%) and wide effective bandwidth (RL<-10 dB) of 14.0 GHz in the thickness range of 1.5-5.0 mm was obtained for the commercial Ni/MWCNTs composites, which is promising for mass production in industrial applications. Our findings offer an effective and industrialized way to design high-performance material to facilitate the research in microwave absorption.

Structural, microstructural, magnetic and electromagnetic absorption properties of spiraled multiwalled carbon nanotubes/barium hexaferrite (MWCNTs/BaFe12O19) hybrid

“…A regularly orientated nucleation of pentagonal, hexagonal and heptagonal carbon rings along the nanotube body plays essential roles in producing a coiled nanotube, and details of its growth mechanisms have been proposed and described previously 16 , 17 . This spiral structure brings advantages in attenuating and EM wave within the material as reported by 18 . On the other hand, short fibre structure improves the performance of EM wave absorption as compared to microparticles 19 .…”

A review of recent advancements in Ni-related materials used for microwave absorption

“…Unfortunately, the encapsulation of magnetic metal particles inside CNTs is not easily achieved unless the CVD technique is applied. After considering the high energy input and low yield of the CVD technique, some groups have chosen to coat CNTs with Ni nanoparticles instead [161][162][163][164][165][166][167]. The coating of CNTs with Ni-based metal nanoparticles can also more or less enhance microwave absorption, but the agglomeration of nanoparticles usually results in severe phase separation, which inevitably limits the loading of nanoparticles on the surfaces of CNTs.…”