Electromagnetic Interference Shield of Highly Thermal-Conducting, Light-Weight, and Flexible Electrospun Nylon 66 Nanofiber-Silver Multi-Layer Film

Abstract

A light-weight, flexible electromagnetic interference (EMI) shield was prepared by creating a layer-structured metal-polymer composite film consisting of electrospun nylon 66 nanofibers with silver films. The EMI shielding effectiveness (SE), specific SE, and absolute SE of the composite were as high as 60.6 dB, 67.9 dB cm3/g, and 6792 dB cm2/g in the X- and Ku-bands, respectively. Numerical and analytical calculations suggest that the energy of EM waves is predominantly absorbed by inter-layer multiple reflections. Because the absorbed EM energy is dissipated as heat, the thermal conductivity of absorption-dominant EMI shields is highly significant. Measured thermal conductivity of the composite was found to be 4.17 Wm−1K−1 at room temperature, which is higher than that of bulk nylon 66 by a factor of 16.7. The morphology and crystallinity of the composite were examined using scanning electron microscopy and differential scanning calorimetry, respectively. The enhancement of thermal conductivity was attributed to an increase in crystallinity of the nanofibers, which occurred during the electrospinning and subsequent hot pressing, and to the high thermal conductivity of the deposited silver films. The contribution of each fabrication process to the increase in thermal conductivity was investigated by measuring the thermal conductivity values after each fabrication process.

Decrease of Fuel Consumption and Emission of 4 Stroke Otto Engine due to Ground Strap Installation

“…Tachometer TA was used to measure engine rotation (Figure 3a) and Muller Beam 10.000 MX analyzed the exhaust gas composition (Figure 3b). Data gathering and analysis to investigate the influence of groundstrap installation on specific fuel consumption and exhaust gas emission uses descriptive quantitative method [11,12].…”

“…The absorbed EMF is changed to heat energy. For this reason, thermal conductivity of ground strap wire as EMF shield is significantly important [12]. Silver is therfore widely used as EMF shiled in many engineering application, e.g.…”

The Role of Electrospun Nanomaterials in the Future of Energy and Environment

“…It should be noted that metal additives with high thermal conductivity increase the thermal conductivity of the polymers as well and facilitate the thermal energy dissipation generated from absorbed energy of EM waves. For instance, Kim et al aimed at improving thermal conductivity of electrospun nylon 66 NFs [ 287 ]. Multi-layer composite films of silver-nylon 66 nanofiber prepared by stacking Ag thin films deposited on nylon 66 nanofiber layers followed by hot pressing and condensing them into a single electrospun mat.…”

Computational Optimizing the Electromagnetic Wave Reflectivity of Double‐Layered Polymer Nanocomposites

“…This trial‐and‐error method is severely restricted by experimental resources, suggesting low efficiency of time and money. Moreover, some efforts have been made to calculate the EM wave reflectivity of multilayered composites; most of them rely on the complex transfer matrix method [ 51,52 ] or commercial simulation software, including COMSOL [ 53,54 ] and CST, [ 55 ] implying considerable difficulty. Therefore, it is still challenging to establish a quantified structure‐performance relationship for layered structures and EM wave reflectivity.…”