In-situ reduction of silver by surface DBD plasma: a novel method for preparing highly effective electromagnetic interference shielding Ag/PET

Electromagnetic interference (EMI) shielding composites with good flexibility and weatherability properties have attracted increased attention. In this study, we combined the surface modification method of sub-atmospheric pressure glow discharge plasma with in situ atmospheric pressure surface dielectric barrier discharge plasma (APSDBD) reduction to prepare polyethylene terephthalate supported silver (Ag/PET). Due to the prominent surface modification of PET film, mild plasma reduction, and effective control of the silver morphology by polyvinylpyrrolidone (PVP), a 3.32 μm thick silver film with ultralow sliver loading (0.022 wt%) exhibited an EMI shielding efficiency (SE) of 39.45 dB at 0.01 GHz and 31.56 dB at 1.0 GHz (>30 dB in the range of 0.01–1.0 GHz). The SEM results and EMI shielding analysis indicated that the high performance originated from the synergistic effect of the formation of silver nanoparticles (AgNPs) with preferentially oriented cell-like surface morphologies and layer-by-layer-like superimposed microstructures inside, which emonstrated strong microwave reflection properties. Fourier transform infrared spectrometer and x-ray diffractometer showed that the surface structures of the heat-sensitive substrate materials were not destroyed by plasma. Additionally, APSDBD technology for preparing Ag/PET had no special equirements on the thickness, dielectric constant, and conductivity of the substrate, which provides an effective strategy for manufacturing metal or alloy films on surfaces of heat-sensitive materials at a relatively low cost.