“…Additionally, the magnetic parameters including saturation magnetization (M s ), remanent magnetization (M r ), coercivity (H c ) are summarized in Table 1 . As reveled, brick do not show any considerable magnetic characteristics, on the other hand, it can be seen that by loading the nanoparticles in the non-magnetic matrix the magnetic parameters is diminished 15 . It is well known that the natural and exchange resonance play the vital role in microwave absorbing and shielding properties 36 .…”
In this research, the energy and shielding efficiency of brick, fabricated by clay soil, as a practical building material was reinforced using CuFe2O4 nanoparticles. Initially, the nanoparticles were fabricated using the sol–gel method and then loaded in the brick matrix as a guest. The architected samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), diffuse reflection spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), vibrating-sample magnetometer (VSM), differential scanning calorimetry (DSC) thermograms, and vector network analyzer (VNA) analyses. IR absorption of the tailored samples was monitored under an IR source using an IR thermometer. IR absorption and energy band gap attested that inserting the nanoparticles in brick medium led to the acceleration of a warming brick, desirable for energy efficiency in cold climates. It is worth noting that the brick/CuFe2O4 nanocomposite achieved a strong reflection loss (RL) of 58.54 dB and gained an efficient bandwidth as wide as 4.22 GHz (RL > 10 dB) with a thickness of 2.50 mm, meanwhile it shielded more than 58% of the electromagnetic waves at X-band by only a filler loading of 10 wt%. The microwave absorbing and shielding characteristics of the composite are mainly originated from conductive loss, electron hopping, natural and exchange resonance, relaxation loss, secondary fields, as well as eddy current loss. Interestingly, the shielding property of the nanocomposite was significantly generated from its absorbing features, reducing the secondary electromagnetic pollutions produced by the shielding materials applying the impedance mismatching mechanism.
“…Additionally, the magnetic parameters including saturation magnetization (M s ), remanent magnetization (M r ), coercivity (H c ) are summarized in Table 1 . As reveled, brick do not show any considerable magnetic characteristics, on the other hand, it can be seen that by loading the nanoparticles in the non-magnetic matrix the magnetic parameters is diminished 15 . It is well known that the natural and exchange resonance play the vital role in microwave absorbing and shielding properties 36 .…”
In this research, the energy and shielding efficiency of brick, fabricated by clay soil, as a practical building material was reinforced using CuFe2O4 nanoparticles. Initially, the nanoparticles were fabricated using the sol–gel method and then loaded in the brick matrix as a guest. The architected samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), diffuse reflection spectroscopy (DRS), field emission scanning electron microscopy (FE-SEM), High-resolution transmission electron microscopy (HRTEM), vibrating-sample magnetometer (VSM), differential scanning calorimetry (DSC) thermograms, and vector network analyzer (VNA) analyses. IR absorption of the tailored samples was monitored under an IR source using an IR thermometer. IR absorption and energy band gap attested that inserting the nanoparticles in brick medium led to the acceleration of a warming brick, desirable for energy efficiency in cold climates. It is worth noting that the brick/CuFe2O4 nanocomposite achieved a strong reflection loss (RL) of 58.54 dB and gained an efficient bandwidth as wide as 4.22 GHz (RL > 10 dB) with a thickness of 2.50 mm, meanwhile it shielded more than 58% of the electromagnetic waves at X-band by only a filler loading of 10 wt%. The microwave absorbing and shielding characteristics of the composite are mainly originated from conductive loss, electron hopping, natural and exchange resonance, relaxation loss, secondary fields, as well as eddy current loss. Interestingly, the shielding property of the nanocomposite was significantly generated from its absorbing features, reducing the secondary electromagnetic pollutions produced by the shielding materials applying the impedance mismatching mechanism.
“…As indicated, all of the fillers have a uniform and smooth morphology. It can be seen that the self-assembly scenario of D-glucose along the hydrothermal process led to the formation of CMS with an average diameter of 600 nm 20 . More interestingly, 2D nanostructures with proper exfoliation and smooth surface of GO and g-C 3 N 4 have been synthesized.…”
Section: Resultsmentioning
confidence: 99%
“…Besides, the observed peaks at 1419, 1273, 1109, and bump at 716 cm −1 are associated with the stretching vibrations of B–O and C–O derivates including B–O–C, B–O–H, C–O–H, and C–O–B, as well as deformation vibration of O–B–O in the borate networks 42 – 46 . It can be seen that some of the peaks related to the conjugated structures have overlapped by the characteristics peaks of hydrogel 14 , 20 , 39 . Figure 3 FTIR spectra of the samples.…”
Section: Resultsmentioning
confidence: 99%
“…The achieved results clarified that the energy band gaps of hydrogel, hydrogel/GO, hydrogel/g-C 3 N 4 , and hydrogel/CMS were 3.90, 1.59, 2.92, and 1.44 eV, respectively. It is found that the inserted structures have regulated the distance between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the fabricated structures, mainly generated from their intrinsic characteristics 20 , 39 . Figure 4 The light absorption ( a ) and transmittance % at λ = 200–800 nm ( b ) of the samples.…”
Section: Resultsmentioning
confidence: 99%
“…Paraffin wax as a conventional polymeric medium was used to investigate the microwave characteristics of the fabricated structures while its composites suffer from the proper mechanical properties. Other matrices including polystyrene, polyvinylidene fluoride, polymethylmethacrylate, silicone rubber, and so on have been widely used to strengthen mechanical properties of the shielding or absorbing structures and reinforce their microwave features 19 , 20 , 23 – 25 . These media promote the practical applications of the microwave absorbing and shielding composites in environmental, industrial, and military fields.…”
In this study, a self-healing hydrogel was prepared that is transparent to visible (Vis) light while absorbing ultraviolet (UV), infrared (IR), and microwave. The optothermal features of the hydrogel were explored by monitoring temperature using an IR thermometer under an IR source. The hydrogel was synthesized using sodium tetraborate decahydrate (borax) and polyvinyl alcohol (PVA) as raw materials based on a facile thermal route. More significantly, graphene oxide (GO) and graphite-like carbon nitride (g-C3N4) nanostructures as well as carbon microsphere (CMS) were applied as guests to more dissect their influence on the microwave and optical characteristics. The morphology of the fillers was evaluated using field emission scanning electron microscopy (FE-SEM). Fourier transform infrared (FTIR) attested that the chemical functional groups of the hydrogel have been formed and the result of diffuse reflection spectroscopy (DRS) confirmed that the hydrogel absorbs UV while is transparent in Vis light. The achieved result implied that the hydrogel acts as an essential IR absorber due to its functional groups desirable for energy efficiency and harvesting. Interestingly, the achieved results have testified that the self-healing hydrogels had the proper self-healing efficiency and self-healing time. Eventually, microwave absorbing properties and shielding efficiency of the hydrogel, hydrogel/GO, g-C3N4, or CMS were investigated, demonstrating the salient microwave characteristics, originated from the established ionic conductive networks and dipole polarizations. The efficient bandwidth of the hydrogel was as wide as 3.5 GHz with a thickness of 0.65 mm meanwhile its maximum reflection loss was 75.10 dB at 14.50 GHz with 4.55 mm in thickness. Particularly, the hydrogel illustrated total shielding efficiency (SET) > 10 dB from 1.19 to 18 and > 20 dB from 4.37 to 18 GHz with 10.00 mm in thickness. The results open new windows toward improving the shielding and energy efficiency using practical ways.
Excellent conductivity and optimized impedance matching are vital for superior absorption-dominated electromagnetic interference (EMI) shielding. An efficient binary electromagnetic filler network regulation method has been proposed. Poly-(vinylidenefluoride)-ferroferric oxide-reduced graphene oxide/ single-wall carbon nanotube (PVDF-Fe 3 O 4 -RGC) composite has been synthesized as a layered segregated polymer composite structure by using an electrostatic assembly and hot compression strategy. Binary electromagnetic filler networks have surpassed the obstacles of magnetic materials in conductive networks, and are thereby beneficial for outstanding conductivity and impedance matching. Therefore, a superior conductivity of 1.28 S cm À1 and an outstanding electromagnetic shielding interference and effectiveness of 44.5 dB have been obtained for loading of 2.02 vol.% single-wall carbon nanotubes (SWCNTs), with an absorption rate larger than 85.0% in the X-band. The enhanced EMI shielding performance is attributed to the regulation of the binary electromagnetic filler network.
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