A Facile Route Preparation of Fe₃O₄/MWCNT/ZnO/PANI Nanocomposite and its Characterization for Enhanced Microwave Absorption Properties

With increasing concerns regarding the potential health risks associated with microwave-based technology, researchers have been actively investigating materials with impressive microwave absorption properties. In this study, a synthesis and investigation of a nanocomposite, named Fe₃O₄/MWCNT/ZnO/PANI, consisting of magnetite (Fe₃O₄), multi-walled carbon nanotube (MWCNT), zinc oxide (ZnO), and polyaniline (PANI) as a microwave-absorbing material, was carried out for the first time. The nanocomposite was prepared through a simple physical mixing approach and demonstrated tunable microwave absorption, making it highly suitable for shielding applications. Structural analysis techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX), confirmed the presence of all components in the nanocomposite. Moreover, ultraviolet-visible spectroscopy (UV-Vis) further verified the formation of nanocomposite components and revealed an adjustable optical bandgap ranging from 2.86 to 3.34 eV. Impressively, the nanocomposite exhibited promising microwave absorption properties, with a minimum reflection loss (RL) of −32.66 dB for the nanocomposite containing 37.50 % PANI by weight, and a maximum electromagnetic bandwidth (EB) of 2.26 GHz for the nanocomposite containing 44.44 % PANI by weight, indicating its potential as an effective shielding material. Furthermore, a modified theory combining transmission line, Landau-Lifshits, and Drude-Lorentz theories was introduced to extract complex relative permittivity and permeability, providing insights into the role of polyaniline in enhancing the microwave absorption properties of the nanocomposite as measured by reflection loss (RL).