Flexible andWater-proof nylon mesh with ultralow silver content for effective electromagnetic interference shielding effectiveness

Abstract

The explosive development of flexible precision electronic devices necessitates materials with ultrahigh electromagnetic interference shielding effectiveness (EMI SE) and excellent mechanical flexibility to suppress unnecessary electromagnetic radiation. Herein, we report a feasible strategy to fabricate a flexible and water-proof porous film for high-efficiency EMI shielding, by utilizing electroless plating of silver (Ag) with the assistance of polydopamine (PDA) and Sn2+ on a commercial nylon mesh (CNM), followed by razor-thin polydimethylsiloxane (PDMS) coating. Results indicate that the fabricated CNM/PDA/Ag/PDMS (CNMAAS) films exhibit continuous coating of Ag nanolayer, which imparts the films perfect electrical conductivity up to 168,060 S/m and ultrahigh EMI SE of up to 91.6 dB, with only 1.38 vol% of Ag loading and 100 μm thickness. The films also exhibit impressive EMI SE enhancement per unit filler and thickness (eg: 4078 dB/vol%/mm and 240.9 dB/wt%/mm for the CNMAAS2 film), owing to the increased interfacial polarization and the conduction loss. Outstanding EMI SE reliability is also achieved for the films, with retentions as high as 96% even suffering 5000 cycles of bending deformation, ascribing to the good mechanical flexibility of porous CNMAAS films. Finally, water-proof, breathable and antibacterial ability of the CNMAAS film were demonstrated. This work provides a facile approach to effectively design and fabricate conductive nanolayers for ultrahigh-performance EMI shielding materials that can be applied in flexible smart electronic devices.