Flexible transparent electromagnetic interference shielding films with silver mesh fabricated using electric-field-driven microscale 3D printing

In order to address the challenging issue regarding the high-efficiency and low-cost fabrication of highperformance flexible transparent electromagnetic interference (EMI) shielding films, a novel approach is proposed to produce flexible transparent EMI shielding film with silver mesh based on electric-field-driven (EFD) microscale 3D printing. The manufacturing principle and the reasonable process parameters are revealed with a series of experiments. Following this fabricating scheme and self-developed EFD micro-scale 3D printer, three flexible transparent EMI shielding films having a size of 60 mm x 60 mm and a line width of 26 mu m are achieved utilizing the low-temperature nano silver paste (75% silver content and 350 dPa.s (25 degrees C) dynamic viscosity). The experimental result shows that the adhesive force between the sintered silver mesh and the polyethylene terephthalate (PET) substrate is measured to be 5B with 3 M scotch tape. The bending experiment proves the excellent mechanical flexibility of the flexible transparent EMI shielding film. In different chemical environments and ultrasonic vibration environments, the silver mesh flexible transparent EMI shielding film can still maintain good electrical properties. When the pitch of the silver mesh is 500 mu m, the optical transmittance is 90.5% and the EMI shielding efficiency for the common medium-high frequency electromagnetic wave is greater than 26 dB. When the pitch is 300 mu m, the optical transmittance is 84% and the shielding efficiency is higher than 32 dB. When the pitch is 150 mu m, the optical transmittance is 69% and the shielding efficiency is higher than 34 dB. As a result, the proposed method provides a promising solution for mass producing high-performance silver mesh flexible transparent EMI shielding films at low cost and high throughput.