Conductive Ag Microspheres with Lychee-like Morphology on the Enhanced Microwave Absorption Properties of MWCNTs

Abstract

The conductive Ag microspheres were designed and prepared by the method of electroless plating via depositing Ag nanoparticles on polystyrene (PS) microspheres. The three-dimensional (3D) absorber hybrids of Ag@MWCNTs were fabricated by the combination of conductive Ag microspheres and multiwalled carbon nanotubes (MWCNTs). The morphology and structure of the absorbents were analyzed and characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, which demonstrated that the Ag@MWCNT hybrids presented a 3D network structure, and the morphology of Ag microspheres was lychee-like. The influence of lychee-like Ag microspheres on the microwave absorption performance of MWCNTs was characterized by a vector network analyzer. The maximum reflection loss (RL) of Ag@MWCNTs was −39.09 dB at 8.10 GHz, of which the bandwidth of RL < −10 dB was 2.00 GHz (7.10–9.10 GHz). In contrast, the PS@MWCNT hybrids had a maximum RL of −22.34 dB at 9.30 GHz. These results indicated that the conductive Ag microspheres with lychee-like morphology were significant to improve the absorption properties of MWCNTs because of the increased conducting pathways and multiple reflection scattering interfaces.

A theoretical investigation of the quarter-wavelength model-part 2: verification and extension

“…There are other problems with current theory such as those discussed in section 3 of Part 1 [18] of this work, that have been unquestionably applied many times among different research groups. Many authors have claimed that a relationship exists between microwave absorption and the morphology of a material [19,20] but this cannot be true as the wavelength of the microwaves and the particle size of the material are so different that the interaction caused by such effect can be neglected just as diffraction cannot occur between microwave and crystal. The film behaves as a uniformed single phase even though its filler is composed by nano-particles with many interfaces between particles.…”

In situ growth of CoNi bimetallic alloys inside polyetheretherketone-derived hierarchical porous carbon as a broadband and efficient electromagnetic wave absorber

“…Furthermore, to determine the EMW attenuation inside composite absorbers, the attenuation constants ( α ) of PC, HPPC, and HPPC/CoNi were calculated based on the equation below: 23,42 …”

The Effect of Surface Roughness of Magnetic Particles on the Electromagnetic Wave Absorbing Performance of Fe3O4/Multiwalled Carbon Nanotubes Hybrids

“…In recent years, combining magnetic Fe 3 O 4 with lightweight MWCNTs is becoming a charming measure to enhance absorbing performance [10,11] . On the one hand, the combination can realize the adjustment of dielectric constant to achieve well EMW absorption through multiple magnetic and dielectric loss mechanisms [12] . MWCNTs rendered the robust conducting channel for electromagnetic field‐induced currents, as well as magnetic Fe 3 O 4 rendered extra magnetic field for induced currents.…”

“…[10,11] On the one hand, the combination can realize the adjustment of dielectric constant to achieve well EMW absorption through multiple magnetic and dielectric loss mechanisms. [12] MWCNTs rendered the robust conducting channel for electromagnetic field-induced currents, as well as magnetic Fe 3 O 4 rendered extra magnetic field for induced currents. The interaction of electrical and magnetic effects resulted rapid decay of microwaves.…”