Development of hybrid maghemite-graphene nanocomposites for terahertz shielding application

• Main Author: Toledo, Samuel Augustus D.
• Format: text
• Language: English
• Published: Animo Repository 2024
• Subjects: Maghemite; Nanoparticle; Terahertz spectroscopy; Physical Sciences and Mathematics
• Online Access: https://animorepository.dlsu.edu.ph/etdm_physics/13; https://animorepository.dlsu.edu.ph/context/etdm_physics/article/1013/viewcontent/2024_Toledo_Development_of_Hybrid_Maghemite_Graphene_Nanocomposites_Full_text.pdf
• Institution: De La Salle University

THz-integrated technology experienced explosive growth and shows excellent potential across many industries. Developing shielding materials is crucial to safeguard waveguides and sensitive devices from unwanted external electromagnetic sources. To date, there is a gap in current research regarding the conclusive use of γ−Fe2O3 NP as an effective nanofiller for THz shielding material while utilizing the inherent properties of GNS as hybrid polymer nanocomposites. Hence, this study aims to develop hybrid γ−Fe2O3-GNS nanocomposites for terahertz shielding applications. The one-step direct chemical exfoliation method synthesized the GNS. In contrast, a straightforward thermal decomposition method synthesized the γ−Fe2O3 NP. The nanomaterials were then loaded to poly (methyl methacrylate) (PMMA), with different ratios of γ−Fe2O3 NP (w%= 0, 5, 10, 15) to fabricate films by evaporative casting technique. Scanning electron microscopy with elemental dispersive x-ray (SEM-EDX) displays the morphological traits of GNS as loosely stacked flat-shaped sheets. The γ−Fe2O3 have predominantly homogeneous spherical-shaped morphology, while the films retained some of the distinct features of the polymer matrix and GNS with localized clusters of the magnetic nanoparticles. Results from the X-ray diffraction (XRD) analysis complemented the results of ATR FTIR analysis, supporting the existence of pure γ−Fe2O3 NP. Moreover, it demonstrates that the γ−Fe2O3 nanoparticles played no role in the polymerization process but functioned solely as an internal filler in the composite. Furthermore, quantitative analysis of THz EMI-SE at 0.6-1.6 THz has shown an SE of ≤ 20 𝑑𝐵 (99.00% wave attenuation) with 15% of y-Fe2O3. These demonstrated improved SE by introducing γ−Fe2O3 NP as an additive magnetic filler. Conclusively, the fabricated hybrid GNS- γ−Fe2O3 nanocomposites were considered facile, effective, and comparable EMI shielding materials in the THz frequency range.