Core-Multishell Heterostructure with Excellent Heat Dissipation for Electromagnetic Interference Shielding.

Herein, we report high electromagnetic interference (EMI) shielding effectiveness of -40 dB in the K _u -band (for a 600 μm thick film) through a unique core-shell heterostructure consisting of a ferritic core (Fe ₃ O ₄ ) and a conducting shell (multiwalled carbon nanotubes, MWCNTs) supported onto a dielectric spacer (here SiO ₂ ). In recent times, materials with good flexibility, heat dissipation ability, and sustainability together with efficient EMI shielding at minimal thickness are highly desirable, especially if they can be easily processed into thin films. The resulting composites here shielded EM radiation mostly through absorption driven by multiple interfaces provided by the heterostructure. The shielding value obtained here is fairly superior among the different polymer nanocomposite-based EMI shielding materials. In addition to EMI shielding capability, this composite material exhibits outstanding heat dissipation ability (72 °C to room temperature in less than 90 s) as well as high heat sustainability. The composite material retained its EMI shielding property even after repeated heat cycles, thereby opening new avenues in the design of lightweight, flexible, and sustainable EMI shielding materials.