Bidirectional Core Sandwich Structure of Reduced Graphene Oxide and Spinnable Multiwalled Carbon Nanotubes for Electromagnetic Interference Shielding Effectiveness

Abstract

Thin and flexible electromagnetic shielding materials have recently emerged because of their promising applications in drones, portable electronics, military defense facilities, etc. This research develops an electromagnetic interference (EMI) shielding material by a bidirectional lattice sandwich structure (BLSS), which is formed by liquid crystalline graphene oxide (LCGO) and an orthogonal pattern of spinnable multiwalled (OPSM) nanotubes in consideration of the movement of electromagnetic waves. The average EMI shielding effectiveness (SE) of the developed material with 0.5 wt % reduced LCGO (r-LCGO) and an OPSM nanotube composed of 64 layers was approximately 66.1 dB in the X-band frequency range (8.2-12.4 GHz, wavelength: 3.5-2.5 cm), which corresponds to a shielding efficiency of 99.9999%. Also, its absorption effectiveness is 99.7% of the total EMI SE, indicating that it has a remarkable ability to prevent secondary damage induced by EM reflection. The specific EMI SE (SSE/t) of the composite material considering the contribution of thickness (t) ranged from 21 953 to 2259 dB cm2/g.