Ag Nanoparticle-Coated Polystyrene Microspheres for Electromagnetic Interference Shielding Films with Low Metal Content

Abstract

The fabrication of thin composite films incorporating metal-based fillers with a delicate structure to achieve high electromagnetic interference shielding effectiveness (EMI SE) at low metal content remains a great challenge. In this work, benefiting from the excellent electrical conductivity of Ag nanoparticles, Ag nanoparticle-coated polystyrene (PS@Ag) microspheres with a large PS core were selected as electrically conductive fillers, and the volume exclusion effect guaranteed the construction of an electrically conductive network with low silver loading. A spontaneous process to construct a segregated laminar structure with a three-dimensional electrically conductive network happened with the assistance of a gravity-driven effect. The flexible thin films with a low amount of silver exhibited outstanding EMI SE per unit thickness (SE/d). To further investigate the effect of the structure on the EMI SE efficiency, it is found that the alternate interfaces play a critical role in enhancing shielding performance by stacking multiple films compared to the bulk films obtained by casting. The EMI SE for an only 0.3 mm triple-piece stacking film with 6.3 wt % Ag loading could reach 55.3 dB compared to 37.2 dB for the triple-thickness casting film. Using the stacking process results in easy accessibility for tailored composites with the desired EMI SE, which supplies a new strategy for the design of shielding materials in the next-generation electronics.

Dual conductive network of nickel‐coated carbon fiber woven fabric for indirect and direct lightning strike protection of carbon fiber reinforced polymer composites

“…Therefore, the reflection loss and magnetic loss by the Ni conductive network and the resistance loss by the CFWF as well as the eddy current loss by Ni‐CFWF result in the excellent EMI shielding performance. In comparison with the existing conductive networks reported by the literature, 29–39 the dual conductive network proposed in this study demonstrate superior EMI capacity and relatively good electrical conductivity (Table 3).…”

“…27 Therefore, the reflection loss and magnetic loss by the Ni conductive network and the resistance loss by the CFWF as well as the eddy current loss by Ni-CFWF result in the excellent EMI shielding performance. In comparison with the existing conductive networks reported by the literature, [29][30][31][32][33][34][35][36][37][38][39] the dual conductive network proposed in this study demonstrate superior EMI capacity and relatively good electrical conductivity (Table 3). 3D network skeleton rGO-ERG/epoxy 68.2 45.9 [29] Hierarchical structure CMF@SiO 2 -CNT/PDMS 50.43 61.34 [30] Lamellar film MXene/GNP-PVDF 7423 36.3 [31] Three-dimensional network PS@Ag/PVA 1060 55.3 [32] Porous film PCPES/Cu 1.82 Â 10 6 59.7 [33] Segregated network Ni@CNTs/Al 2 O 3 103.1 41.8 [34] Anisotropic conductive network Ti 3 C 2 T x /ANF 854.9 65.5 [35] Sandwich-structured network FA-CNF/MXene/FA-CNF 31,680 63.8 [36] Asymmetric conductive network C-ZIF67/GNP 6173 50.5 [37] Gradient structure Cotton/AgNWs/PVDF@GO 4.5 Â 10 À2 50 [38] Asymmetric conductive structure a-EP/f-RGO x /Ni-chains 5 10 À1 40.82 [39] Dual ).…”