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Updated: Dec 25, 2025

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites
Published on: September 19, 2020
Tuning of Shells in Trilaminar Core@Shell Nanocomposites in Controlling Electromagnetic Interference through
Kunal Manna1, Suneel Kumar Srivastava1
1Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India 721302.
Abstract:
Fe3O4@SiO2@PPy core-shell nanocomposites were fabricated by the coating of SiO2 on Fe3O4 through base catalyzed hydrolysis of tetraethyl orthosilicate followed by encapsulation of polypyrrole (PPy). Subsequently, these trilaminar composites have been characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller, superconducting quantum interference devices, and measurement of the total shielding efficiency in the frequency range of 2-8 GHz. Our findings showed the highest total shielding efficiency (∼32 dB) of Fe3O4@SiO2@PPy (Fe3O4@SiO2/pyrrole wt/wt = 1:9) and followed reflection as the dominant shielding mechanism. Such performance was attributed to poor impedance matching between the PPy (conducting)/SiO2 (insulating) and high electrical conductivity of Fe3O4@SiO2@PPy. Alternatively, electromagnetic (EM) waves incident on the SiO2@PPy interface could also account for enhancing the total shielding efficiency of Fe3O4@SiO2@PPy because of multireflection/refraction. Our earlier work also showed excellent total shielding efficiency of Fe3O4@C@PANI nanocomposites, through absorption as the dominant shielding mechanism. These findings clearly suggest that EM interference shielding in Fe3O4@SiO2@PPy and Fe3O4@C@PANI trilaminar core@shell nanocomposites is controlled by tuning of the shells through switching of the mechanism.
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