Multiscale Assembly of Grape-Like Ferroferric Oxide and Carbon Nanotubes: A Smart Absorber Prototype Varying Temperature to Tune Intensities

Abstract

Ideal electromagnetic attenuation material should not only shield the electromagnetic interference but also need strong absorption. Lightweight microwave absorber with thermal stability and high efficiency is a highly sought-after goal of researchers. Tuning microwave absorption to meet the harsh requirements of thermal environments has been a great challenge. Here, grape-like Fe3O4-multiwalled carbon nanotubes (MWCNTs) are synthesized, which have unique multiscale-assembled morphology, relatively uniform size, good crystallinity, high magnetization, and favorable superparamagnetism. The Fe3O4-MWCNTs is proven to be a smart microwave-absorber prototype with tunable high intensities in double belts in the temperature range of 323-473 K and X band. Maximum absorption in two absorbing belts can be simultaneously tuned from ∼-10 to ∼-15 dB and from ∼-16 to ∼-25 dB by varying temperature, respectively. The belt for reflection loss ≤-20 dB can almost cover the X band at 323 K. The tunable microwave absorption is attributed to effective impedance matching, benefiting from abundant interfacial polarizations and increased magnetic loss resulting from the grape-like Fe3O4 nanocrystals. Temperature adjusts the impedance matching by changing both the dielectric and magnetic loss. The special assembly of MWCNTs and magnetic loss nanocrystals provides an effective pathway to realize excellent absorbers at elevated temperature.

Synthesis of Zn(II)-Doped Magnetite Leaf-Like Nanorings for Efficient Electromagnetic Wave Absorption

“…Hence, the substitution of Fe 2+ by Zn 2+ leads to enhanced polarization which then contributes to increased permittivity. On the other hand, plenty of nanorings build a conductive network for electrons hopping and migrating37, which could lead to increased conductivity and thus contributed enhanced electric polarization38. As previously reported by Tong et al 10.…”

Synthesis, characterization, interfacial interactions, and properties of reduced graphene oxide/Fe3O4/polyaniline nanocomposites

“…For this situation, researchers have made great efforts on absorption materials. Such as Cao have done a lot of research on the microwave absorption properties of carbon materials (CNT, graphene) and their composites. They have made in‐depth explorations of the microwave absorption properties of materials in different frequency and wide temperature range.…”

“…They have made in‐depth explorations of the microwave absorption properties of materials in different frequency and wide temperature range. For example, Cao built composite of grape‐like Fe 3 O 4 /CNT structure and obtained high‐efficiency microwave absorption properties in the temperature range of 323–473 K and X band. Huang made many studies on preparation, morphology control, and element doping etc.…”

Enhanced electromagnetic wave absorption of Fe‐doped silicon oxycarbide nanocomposites

“…In recent years, PDC‐based absorbing materials have been receiving considerable attention due to their high temperature resistance, good oxidation resistance, and regulable structures . However, the sole PDCs are not suitable for EMI absorbing materials considering their insufficient dielectric loss . To overcome this issue, considerable researches have been devoted to improve the EMI absorbing capability of the PDC.…”

“…[34][35][36][37][38][39][40] However, the sole PDCs are not suitable for EMI absorbing materials considering their insufficient dielectric loss. [41][42][43][44] To overcome this issue, considerable researches have been devoted to improve the EMI absorbing capability of the PDC. Liu et al 45 fabricated an RGO/CNTs-SiCN nanocomposite with the minimum reflection loss value (RL min ) of −67.20 dB at a thickness of 2.00 mm.…”