Abstract
Graphene has been regarded as one of the most promising two-dimensional nanomaterials. Even so, graphene was still faced with several key issues such as impedance mismatching and narrow bandwidth, which have hindered the practical applications of graphene-based nanocomposites in the field of microwave absorption materials. Herein, a series of Si-modified rGO@Fe3O4 composites were investigated and fabricated by a simple method. On one hand, the degree of defects in graphene carbon could be tuned by different silane coupling reagents, which were beneficial to enhancing the dielectric loss. On the other hand, the spherical Fe3O4 nanoparticles provided the magnetic loss resonance, which contributed to controlling the impedance matching. Subsequently, the electromagnetic absorption (EMA) properties of Si-modified rGO@Fe3O4 composites with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) were investigated in this work. As a result, the Si(2)-rGO@Fe3O4/PVDF-co-HFP composite exhibited the excellent EMA performance in the range of 2–18 GHz. The maximum reflection loss (RLmax) reached −32.1 dB at 3.68 GHz at the thickness of 7 mm and the effective absorption frequency bandwidth for reflection loss (RL) below −10 dB was 4.8 GHz at the thickness of 2 mm. Furthermore, the enhanced absorption mechanism revealed that the high-efficiency absorption performance of Si(2)-rGO@Fe3O4/PVDF-co-HFP composite was attributed to the interference absorption (quarter-wave matching model) and the synergistic effects between Si(2)-rGO@Fe3O4 and PVDF-co-HFP. This work provides a potential strategy for the fabrication of the high-performance EMA materials.
Highlights
With the rapid propagation of the electronic devices—especially personal mobile phones, satellite communication, radar detectors, and other communication devices—electromagnetic waves (EMW), taken as “pollution”, are growing to be a huge threat to human health and has been attracted consideration attention [1]
The complex magnetic loss covers weaker values contrast to the dielectric loss. These results suggest that the electromagnetic absorption (EMA) performance of Si-modified reduced graphene oxide (rGO)@Fe3 O4 /PVDF-co-HFP composites is mainly attributed to dielectric loss rather than magnetic loss
Permeability parameters the abundant of wrinkles in Si(2)-rGO would provide a channel for improving the multiple-reflection (μ’ and μ’’) and Co curve indicated that magnetic loss effect of Fe3O4 NPs in S2 sample mainly resulted of EMW (Figure S1b,c, Supplementary Materials)
Summary
With the rapid propagation of the electronic devices—especially personal mobile phones, satellite communication, radar detectors, and other communication devices—electromagnetic waves (EMW), taken as “pollution”, are growing to be a huge threat to human health and has been attracted consideration attention [1]. Except for group reported that the nitrogen-doped sheet exhibited the excellent performance in optimizing EM parameters by tuning the degree of defects in rGO, rGO combined with other magnetic the G band (5.6–8.2 GHz) and X band (8.2–12.4 GHz) due to the existence of the lattice defects in loss materials, such as, CoNi [13], CoFe2 O4 [17,18], FeCo [18], Fe3 O4 [19], and Fe@Fe3 O4 [20], is nitrogen-doped rGO [16]. 4 nanoparticles are directly packaged on packaging can beresults difficult to predict, making difficult tomatching obtain composite behavior at a large sheet, these contribute to optimizing theitimpedance and enhance the EMW scaleattenuation [23,24] This charge transfer between magnetic lossy materials caniteasily [21,22]. /PVDF-co-HFP composites was[31,32]
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