Epoxy/CNT-Zn0.5Ni0.5Fe2O4 Multilayer Polymeric Nanocomposites for Electromagnetic Wave Absorption

Highly efficient electromagnetic interference (EMI) shielding has been attracting extensive attention. However, it still remains a challenge to fabricate EMI shields with excellent absorption performance. In this regard, epoxy-based nanocomposites with multilayer structures containing carbon nanotube (CNT) and Zn0.5Ni0.5Fe2O4 (ZnNiFe) nanoparticles are designed for EMI shielding applications. The epoxy/CNT-ZnNiFe nanocomposites show excellent EMI shielding absorption performance attributed to high dielectric and magnetic loss combined with internal-reflection. The 4-layer nanocomposite absorbs more than 61% of the incident wave with a reduced shielding effectiveness by reflection (SER) compared to its single-layer counterpart. Moreover, it is revealed that the 4-layer nanocomposite possesses a shielding performance of approximately 20% higher than the 2-layer nanocomposite at the same thickness and filler content, expressing the prominent role of the multilayer structuring in shielding performance. More importantly, the 4-layer sample shows an absorption coefficient of 0.61, translating to absorption of more than 61% of the incident wave. Besides, the 4-layer nanocomposite switches the shielding mechanism from reflection to absorption in comparison with the single-layer samples (at the same thickness). This research study reveals that the multilayer nanocomposites can open up an effective and new way for EMI shielding nanocomposite designers.