Superior Multifunctional Nickel Ferrite Nanoparticles and Graphite-Integrated Thermoplastic Polyurethane Nanocomposites for Electromagnetic Interference Shielding, Joule Heating, and Photothermal Applications

The introduction of next-generation electronic devices, multimedia communication, and the miniaturization of the electronics industry has emphasized the need for the development of lightweight electromagnetic interference (EMI) shielding materials. Herein, we fabricated thermoplastic polyurethane (TPU)-based nanocomposites incorporated with conducting filler graphite (G) and magnetic filler nickel ferrite (NF) nanoparticles using the melt-mixing approach with varying amounts of conducting and magnetic filler. The developed G40NF5@TPU nanocomposite, comprising 40 wt % graphite and 5 wt % NiFe2O4 nanoparticles, exhibited superior EMI shielding performance with a total EMI shielding effectiveness of 41.6 dB, capable of blocking 99.99% of incident radiation in the 8.2–12.4 GHz frequency range at a thickness of only 1.95 mm. To elucidate the mechanisms contributing to the high shielding performance, various factors were analyzed, highlighting the roles of high dielectric, magnetic, and conduction losses in achieving superior attenuation. Beyond EMI shielding, the G40NF5@TPU nanocomposite exhibited a remarkable, stable, and durable electrothermal conversion response, with a surface temperature reaching up to ∼154 °C at a low driving voltage of 7 V. The developed G40NF5@TPU nanocomposites also exhibited a stable photothermal response, achieving surface temperatures of up to ∼37 °C under mild solar-simulated irradiation. The synergistic combination of superior EMI shielding performance, efficient electrothermal and photothermal conversion capabilities, and hydrophobicity highlights the remarkable versatility of the G40NF5@TPU nanocomposite. Owing to these combined features, G40NF5@TPU emerges as a highly promising candidate for next-generation electronic and communication devices, personal thermal management devices, defense and aerospace components, and other advanced technologies that require both robust EMI protection and efficient thermal regulation in harsh or variable environments.