Synergistic Enhancement of EMI Shielding Performance in Polymer Nanocomposites through Actinide and Reinforcing Nanofillers

Abstract

Flexible and lightweight polymer nanocomposites with high electromagnetic interference (EMI) shielding efficiency are highly desirable for advanced electronic and communication systems. In this work, conductive polyaniline (PANI) was synthesized by chemical oxidative polymerization, while thorium cobalt oxide (Th2CoO5) nanoparticles were prepared using a solution combustion method. Flexible PVA/PANI/Th2CoO5@HNT nanocomposite films with varying filler compositions were fabricated and systematically investigated for their structural, electrical, mechanical, thermal, and EMI shielding properties. X-ray diffraction and Fourier transform infrared spectroscopy confirmed the successful incorporation of Th2CoO5 and halloysite nanotubes (HNT) into the semicrystalline polymer matrix with strong interfacial interactions. Scanning electron microscopy revealed uniform dispersion of tubular HNT and granular Th2CoO5, promoting interconnected networks for enhanced polarization and electromagnetic attenuation. Electrical characterization demonstrated improved AC conductivity and enhanced dielectric and magnetic loss behavior due to conductive pathways and interfacial polarization. EMI shielding measurements in the X-band (8.2–12.4 GHz) showed absorption-dominated shielding, with the PVA/PANI/4 wt%Th2CoO5@4 wt%HNT composite achieving a maximum total shielding effectiveness of ∼67 dB through the synergistic effects of conduction loss, dielectric relaxation, and interfacial polarization. Thermal analysis indicated enhanced stability with increasing HNT content, while the PVA/PANI/4 wt%Th2CoO5@4 wt%HNT composite exhibited the highest tensile strength of ∼24 MPa with excellent flexibility. These findings demonstrate the potential of PVA/PANI/Th2CoO5@HNT nanocomposites as multifunctional materials for high-performance EMI shielding applications.