Silver-Sandwiched Natural Rubber/St-LDH/MWCNT Hybrid Bio-Nano-Composite System as a High-Performing Multimedia Laminated Electromagnetic Interference Shield Through a Tripling Mechanism

Abstract

High-performance electromagnetic interference (EMI) shields are extremely important to protect human beings and sophisticated electronic devices from harmful EM radiation emissions in this digital age. Herein, a novel multimedia laminated system based on silver nanosheet-sandwiched natural rubber/stearic acid-modified layered double hydroxide/multiwalled carbon nanotube hybrid bio-nano-composites [NR/St-LDH/MWCNT]-Ag-[NR/St-LDH/MWCNT] has been fabricated successfully. The fabricated nanocomposite presents a remarkably high electromagnetic interference shielding efficiency (EMI-SE) of −28 dB in the absence of a silver sheet and an enhanced EMI-SE of −84 dB in the presence of a silver nanosheet. The very low percolation threshold of MWCNT (0.009) and the maximum dielectric strength of the NR/St-LDH/MWCNT hybrid biocomposite (15,556) satisfied the criteria for the composite to act as an EMI shield. The mechanism behind this significant enhancement that is tripling in the EMI-SE value of this novel hybrid material is analyzed in detail. An EM absorption process through an innovative tripling mechanism is proposed for the first time by interpreting experimental results. In the tripling mechanism, the first hybrid nanocomposite sheet absorbs radiation and the light thence transmitted from the first sheet is reflected back to the same sheet by the sandwiched silver sheet for further absorption and the residual light transmitted from the silver sheet is absorbed by the second hybrid nanocomposite sheet. The absorbing efficiency of the silver-sandwiched system was found to be 99.999%, which is a shred of solid evidence for the tripling mechanism. Further, detailed physico-chemical and EMI shielding efficiency measurements indicate that the proposed hybrid material can be used as a very smart, lightweight shielding material for future EMI shielding applications.