Carbon Allotropes-Based Paints and Their Composite Coatings for Electromagnetic Shielding Applications

Abstract

The present manuscript reports on optimized formulations of alcohol-based conductive paints for electromagnetic interference shielding (EMI), which can ensure compatibility and reduce the visibility of electronic equipment, as a continuation of our previous work in this field, which examined water-based formulations for other applications. Graphite, carbon black, graphene, Fe3O4, Fe ore, and PEDOT:PSS in various ratios and combinations were employed in an alcohol base for developing homogeneous paint-like fluid mixtures that could be easily applied to surfaces with a paintbrush, leading to homogeneous, uniform, opaque layers, drying fast in the air at room temperature; these layers had a reasonably good electrical conductivity and, subsequently, an efficient EMI-shielding performance. Uniform, homogeneous and conductive layers with a thickness of over 1 mm without exfoliations and cracking were prepared with the developed paints, offering an attenuation of up to 50 dB of incoming GHz electromagnetic radiation. The structural and morphological characteristics of the paints, which were studied in detail, indicated that these are not simple physical mixtures of the ingredients but new composite materials. Finally, mechano-climatic and environmental tests on the coatings demonstrated their quality, since temperature, humidity and vibration stressors did not affect them; this result proves that these coatings are suitable for commercial products.

Synthesis and Application of Ion-Exchange Magnetic Microspheres for Deep Removal of Trace Acetic Acid from DMAC Waste Liquid

“…Figure 2 a shows the FT-IR spectra of Fe 3 O 4 , Fe 3 O 4 @SiO 2 , and Fe 3 O 4 @SiO 2 @N(CH 3 ) 3 + , respectively. For all the microspheres, a peak at 585 cm −1 corresponded to the Fe-O stretching vibration [ 23 ]. The peaks located between 1000 and 1250 cm −1 , as well as those at 798 cm −1 , assigned to the stretching mode of Si-OH and Si-O-Si in silica [ 24 ], respectively, indicating that the silicon layers were successfully coated on the surface of Fe 3 O 4 by the sol-gel method.…”

Comparative Study of Graphene Nanoplatelets and Multiwall Carbon Nanotubes-Polypropylene Composite Materials for Electromagnetic Shielding

“…The shielding performance methodology of the developed materials was presented in detail in our previous studies [ 10 , 12 ], in terms of shielding effectiveness, a parameter that depends on several factors related to both the material and the design used; shielding effectiveness can be expressed as: where P i is the incident and P t the transmitted wave; E i and E t are incident and transmitted electric fields, respectively.…”

“…For the scope of this study, the parameter S 21 was recorded and related to each composite material as a function of frequency in a bandwidth of 4 GHz to 9 GHz. The measuring setup used for the determination of the shielding performance of the developed PP-based materials was similar to the one presented in previous studies [10,12], and it was based on the Keysight vector network analyzer (VNA) N9923A (1400 Fountaingrove Parkway, Santa Rosa, CA, USA), two waveguide to coax adapters, and a diaphragm (holder for sample). The waveguides had a cut-off frequency of 4.3 GHz, resulting in a measurement range between 4.3 and 9 GHz.…”

“…Traditional solutions consisting of the use of metals are becoming obsolete. Miniaturization and the need for fabrication of light devices and infrastructure determined the imperative development of alternative solutions like paints, sprayable solutions, and functional plastics and rubbers with EMI shielding properties [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ].…”

A theoretical focus on nanoparticle attenuation capabilities for potential utilizations in radiation protect: TiO2-SiO2-Fe3O4-B4C-Al2O3

“…and magnetic particles, such as Fe 3 O 4 [20][21][22][23], have shown promise as shielding materials due to their radiation attenuation properties and low toxicity.…”