Design of Flame-Retardant, Hydrophobic, Ultrathin, Lightweight and Flexible EMI shielding Fabric and Sheets for Defense, Space & Industrial Applications

This work presents the fabrication of flame retardant, hydrophobic, lightweight, ultrathin fabric and sheet samples with very high EMI shielding properties. In this study, a PVDF polymer solution with pre-optimized concentrations of highly conductive nanofillers containing exfoliated graphite, carbon nanofiber, and silver nanoparticles is prepared. This conductive polymer solution is directly mold cast to make a sheet sample and the same solution is coated over cotton fabric to make a fabric sample. The FESEM images show the random distribution of nanofillers forming a conductive network, while TGA analysis confirms the high flame retardancy of these samples up to 300°C. The sheet sample shows a high EMI shielding efficiency of more than 37 dB in the complete X-band for a thickness of 0.20 mm as compared to the fabric sample, which shows more than 20 dB shielding efficiency in the complete X-band for a thickness of 0.315 mm. The high shielding value is achieved due to the formation of a continuous 3D conductive network of nanofiller across the whole body of sheet samples as compared to the fabric-based sample. The experimental results suggest that these samples could be applied for various military, space, and industrial applications.