Core–Multishell\nHeterostructure with Excellent Heat Dissipation for Electromagnetic\nInterference Shielding

Abstract

Herein, we report\nhigh electromagnetic interference (EMI) shielding effectiveness of\n−40 dB in the K_u-band (for a 600 μm thick\nfilm) through a unique core–shell heterostructure consisting\nof a ferritic core (Fe₃O₄) and a conducting\nshell (multiwalled carbon nanotubes, MWCNTs) supported onto a dielectric\nspacer (here SiO₂). In recent times, materials with good\nflexibility, heat dissipation ability, and sustainability together\nwith efficient EMI shielding at minimal thickness are highly desirable,\nespecially if they can be easily processed into thin films. The resulting\ncomposites here shielded EM radiation mostly through absorption driven\nby multiple interfaces provided by the heterostructure. The shielding\nvalue obtained here is fairly superior among the different polymer\nnanocomposite-based EMI shielding materials. In addition to EMI shielding\ncapability, this composite material exhibits outstanding heat dissipation\nability (72 °C to room temperature in less than 90 s) as well\nas high heat sustainability. The composite material retained its EMI\nshielding property even after repeated heat cycles, thereby opening\nnew avenues in the design of lightweight, flexible, and sustainable\nEMI shielding materials.