Conducting Polymer-Based Magnetically Active Nanocomposites for Microwave Shielding Materials

Abstract

The aggregation of electromagnetic radiation within the spatial environment leads to the disruption of electronic devices used in commercial and military sectors, potentially causing adverse effects on human well-being. There is a growing need for effective shielding materials to manage electromagnetic interference (EMI) and its related issues. It is widely acknowledged that single-composition materials are insufficient in providing the necessary EMI shielding efficiency. As a result, conducting polymer-based composites have garnered significant attention due to their distinctive characteristics, including their light weight, processability, environmental stability, extended lifespan, durability, reduced corrosiveness, and tunability. In this work, the synthesis of conducting polymer nanocomposites consisting of polypyrrole (PPY) and polyaniline (PANI) with nickel and cobalt ferrite nanoparticles was achieved using emulsion polymerization. The ferrite nanoparticles, on the other hand, were synthesized using the sol–gel technique. The investigation focused on examining the microwave absorption characteristics of the composite material within the frequency range of 8.2–12.4 GHz, often referred to as the X-band. The composites based on PANI exhibited remarkably favourable shielding behaviour, attributed primarily to their increased conductivity, resulting in shielding effectiveness of 36 dB (~99.9%). Conversely, the composites based on PPY achieved shielding effectiveness of 25 dB. It is worth noting that the shielding efficiency of both composites was influenced by the magnetization characteristics of the ferrite nanoparticles. The superior shielding properties of absorption, compared to reflection, make composites very promising materials for several applications, including stealth technology and radar absorption.