Lightweight poly (vinylidene fluoride)/silver nanowires hybrid membrane with different conductive network structure for electromagnetic interference shielding

摘要

Electromagnetic interference (EMI) shielding materials with silver nanowires (AgNWs) have been widely reported to deal with electromagnetic radiation pollution. However, few studies focus on the effect of the spatial distribution of the AgNWs on the shielding performance of materials. In this work, poly(vinylidene fluoride) (PVDF)/AgNW hybrid electrospun membranes were prepared through dip-coating and spray-coating of AgNWs, respectively, and the morphology features and EMI shielding effectiveness (SE) of dip-coated and spray-coated hybrid membranes were investigated. The results show that the AgNWs in dip-coated samples form three-dimensional (3D) networks and those in spray-coated samples form a two-dimensional (2D) layer. EMI SE of dip-coated sample is higher than that of the spray-coated sample at the same area density of AgNWs, though the electrical conductivity of the spray-coated sample can be higher than that of the dip-coated sample. At 900 mg/m(2)for area density of AgNWs, EMI SE of the dip-coated sample can reach 58.7 dB, and EMI SE of the spray-coated sample does not exceed 33.4 dB owing to that the 3D AgNW networks formed by dip-coating are beneficial for multiple reflection and interfacial polarization. A higher concentration of AgNW dispersion for dip-coating leads to a more excellent EMI shielding performance, and the specific SE of the sample by dip-coating in 0.5 wt% AgNW dispersion can reach 6.62 x 10(4) dBcm(2)/g due to the high SE of 107.2 dB and low density and thickness. These results reveal the effect of the structure of the AgNW networks on the EMI shielding performance of the hybrid membrane.