Enhanced electromagnetic interference shielding properties of phenolic resin derived lightweight carbon foam decorated with electrospun zinc oxide nanofibers

Abstract

The incessant technological advancement has led to excessive usage of electronics and telecommunication devices. This, however, has created a critical electromagnetic (EM) pollution concern. EM pollution affects the functioning of highly sensitive electronic devices and is hazardous to human health. While several metallic or polymeric materials have been employed to combat this concern, however, most of them suffer from many intrinsic limitations. Herein, we developed novel lightweight carbon foam (CF) decorated with zinc oxide nanofibers (ZONF) for high-performance electromagnetic interference (EMI) shielding. First, the CF was synthesized from the phenolic resin using the polyurethane (PU) foam impregnation method followed by carbonization, and then as prepared CF was decorated by ZONF using the electrospinning method. The EMI shielding effectiveness (SE) and relative complex permittivity of decorated foams were examined by vector network analyzer in X band (8.2–12.4 GHz) at the thickness of 2.0 mm. It was found that the open porous structure and ZONF can synergistically enhance the EMI shielding properties. The impedance matching and interfacial polarization provided by the porous structure and ZONF lead to improve the EM wave absorption performance in CFs. Due to the decoration of ZONF, the resultant CF exhibited excellent absorption-dominant with an EMI SE of 58.6 dB and a specific EMI SE of 1046 dB cm2 g−1 at only 0.28 g/cm3 density. Thus, the lightweight ZONF decorated CF is a promising material for aerospace and next-generation smart devices.