Hybridization-Induced Polarization of Graphene Sheets by Intercalation-Polymerized Polyaniline toward High Performance of Microwave Absorption

Abstract

An intercalation polymerization is applied to regulate the hybridizing structures of polyaniline@graphene (PANI@GE). Polarization of GE sheets is realized, which is attributed to the hybridization by the in situ intercalation-polymerized PANI molecules. The polarizing effect on GE is confirmed by characterizations and density functional theory calculations, and the results indicate that distinct p−π and π–π interactions exist between the PANI molecules and the GE sheets. As a result, this new structural hybrid leads to a high performance of microwave absorption. The minimum reflection loss (RL) of the optimized PANI@GE hybrid can be as low as −64.3 dB at 10.1 GHz with the RL bandwidth of −10 dB being 5.1 GHz (from 8.6 to 13.7 GHz). A further study reveals a special mechanism for the electromagnetic energy consumptions by the structural resonance of the polarized GE-based hybrids, a complex macromolecule. In addition, the fully separated GE provides a good impedance matching, together with the widely held multiscaled relaxations of the interfacial polarization.

Multiaxial electrospun generation of hollow graphene aerogel spheres for broadband high-performance microwave absorption

“…However, it can be obviously observed that the peak of HGAS and BGAS at G band is gradually down-shifted to 1,588 and 1,586 cm −1 respectively after thermal reduction, which can be attributed to the recovery of the hexagonal network of carbon atoms with defects [22]. The D/G intensity ratio increased, which is typically stated to be due to the decrease in the average size of the sp 2 domains that is typically stated as arising from new (or more) graphitic domains being formed and the sp 2 cluster number increasing [4]. Furthermore, The broad 2D peak at 2,710.4 cm −1 indicates the turbostratic structure in the stacking of graphene sheets [6].…”

“…Meanwhile, a new broad peak at around 22.5 o can also be found, this may be attributed to the partial stacking of GO sheets which are incompletely oxidized due to the squeezing effect of the ice crystals [23]. After thermal reduction to HGAS and BGAS, a sharp peak at 25.3 o appears with the disappearance of the HGOAMs diffraction peaks, which attributes to the re-stacking of graphene layers and indicates the efficient deoxygenation of GO sheets and a highly crystalline "graphitic" structure after annealing [4]. Besides, a weak peak locating at 43° is the evidence of the turbostratic structure, which is consistent with the Raman data.…”

“…Most GA are fabricated by hydro/solvothermal [18,19], sol-gel reactions [20], freeze casting [4], but lacking structural ordering of pores owing to the random stacking integration of graphene oxide (GO) or graphene nanosheets. A templatedirected chemical vapor deposition or recent 3D printing method can be used to design and construct the intricate internal structures as well as complex external architectures [3,21].…”

Improved impedance matching by multi-componential metal-hybridized rGO toward high performance of microwave absorption

“…The complex permittivities of these synthesized hybrids are given in Figure 5(a and b). Both the real and imaginary parts decrease with an increase in frequency, indicating a frequency dispersion behavior induced by the enhanced polarization lagging in the high frequency [46,47]. The dielectric behaviors of McM@rGO majorly originate from the interfaces between nanoparticles and graphene layers as well as the polarization of residual functional groups [48].…”

A Facile Synthesis of Novel Amorphous TiO2 Nanorods Decorated rGO Hybrid Composites with Wide Band Microwave Absorption

“…Nowadays, with the rapid development of electronic information technology, electromagnetic radiation and pollution originating from electronic devices pose a threat to human health and information safety [1][2][3][4][5][6] and consequently the design and fabrication of microwave absorption materials which can dissipate microwave energy efficiently has become an urgent requirement [7][8][9]. In recent years, extensive efforts on the design of microwave absorbers have been focused on strengthening reflection loss (RL), broadening absorption bandwidth and reducing weight as well as thickness.…”