Multi-layered composites using polyurethane-based foams and 3D-printed structures to curb electromagnetic pollution

Abstract

Herein, a comparative study of the electromagnetic interference (EMI) shielding performance of multi-layered architectures fabricated using different strategies (i.e., polyurethane (PU)-based film, foam, and 3D printed structures) has been evaluated. The key attributes, i.e., conductivity and various losses towards efficient attenuation of the incoming EM radiation, were achieved by incorporating multiwalled carbon nanotubes (CNTs) and ferrite-decorated reduced graphene oxide (rGO–Fe₃O₄) strategically in the multi-layered structure. To fabricate the multi-layered architecture, rGO–Fe₃O₄ was incorporated in polyvinylidene difluoride (PVDF) and the CNTs in the polycarbonate (PC) as the two outer layers of the architecture. PU-based structures (film or foam or 3D printed mesh) containing CNTs were fabricated and sandwiched between the PC and PVDF composite films to develop multi-layered architecture with improved shielding performance. The novelty of this work lies in the fabrication and shielding study of such porous-layered composite structures and comparing them with non-porous counterparts. The results suggested that amongst all the fabricated structures, the PU–CNT foam-based multi-layered structure showed a high shielding effectiveness (SE_T) value of −39 dB in the K-band, with absorption-dominated shielding (91% and above). In order to further enhance the shielding effectiveness, Ag was sputtered on the PU-foam, which resulted in the highest SE_T value of −50 dB in the X-band. The results presented here begin to suggest that in-situ synthesized foam with non-uniform and dead pores enhances the shielding performance compared to 3D printed mesh structures or non-porous structures.