Search

Endowing electromagnetic interference (EMI) shielding foams with ultralow density and dynamic stable structure is crucial yet challenging. Here, we propose a facile one-step thermal treatment strategy to fabricate lightweight silver/reduced graphene oxide-coated carbonized melamine (CMF/rGO/Ag) hybrid foams with remarkable mechanical performance and outstanding EMI shielding effectiveness (EMI SE). Due to interfacial reinforcement of rGO between CMF skeleton and silver, the CMF/rGO/Ag foams show outstanding structural stability after 1000 cycles of a loading-unloading compression test. Moreover, The EMI SE of the foams reaches 50.6 dB at a mere density of 16 mg cm−3. The normalized surface-specific SE is up to 7616 dB cm2 g−1 with an ultralow Ag content of 0.09 vol%. Interestingly, the collaboration of the porous skeleton and multiple interfaces contribute to an anomalous high absorption coefficient of CMF/rGO/Ag foams (over 0.5). The high-absorption-coefficient shielding mechanism of the CMF/rGO/Ag foams was further studied by finite element analysis (FEA). The remarkable near-field EMI shielding performance of the CMF/rGO/Ag foam demonstrates that the low density and robust CMF/rGO/Ag foam have enormous advantages and wide application prospects as EMI shielding materials of electronic packaging. A silver/rGO coated carbonized melamine foam is fabricated by a one-step thermal treatment process. The as-prepared hybrid foams show excellent mechanical properties and structural stability. Due to the unique porous structure, the hybrid foams demonstrate an outstanding specific EMI SE of 7176 dB cm2 g-1, and an extra-high absorption coefficient of 0.51 with a low Ag content of 0.09 vol%. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The AgFD/PVDF composite films featured with double structures were fabricated. • The AgFD layer was firstly deposited followed by incorporating of PVDF. • The ultra-thin composite films exhibit remarkable EMI SE at low AgFD loadings. • The composite films possess high flexibility and mechanical strength. With the electronic products move towards to flexibility, miniaturisation and high frequency, conductive polymer composites (CPCs) with ultra-low thickness, outstanding electromagnetic interference (EMI) shielding effectiveness (SE) and excellent mechanical property are urgently needed. In this work, silver fractal dendrite/polyvinylidene fluoride (AgFD/PVDF) composite films featured with double structures (defined as two-step films) were fabricated by depositing an AgFD layer followed by the incorporating of PVDF. Thanks to the 3D fractal structures of AgFDs and highly efficient conductive network, the as-prepared two-step films exhibit high electrical conductivity of 4.18 × 104 S·m−1 at only 10 wt% AgFD loading and about 4.18 × 105 S·m−1 at 40 wt% loading. The excellent electrically conductive property endows the two-step films to achieve remarkable EMI SE of 46.8 dB in X-band and 42.7 dB in Ka-band at 10 wt% loading with thickness of 27 μm, and 83.3 and 105.0 dB with thickness of 33 μm as the AgFD loading up to 40 wt%, respectively. The two-step films also show high near-field EMI SE values of 46.9 ∼ 61.4 dB, which fully meets the practical commercial requirements. Additionally, the two-step films possess high flexibility and mechanical strength. Considering the outstanding electrically conductive, EMI shielding performances and excellent mechanical property, the two-step composite films present a huge potential for practical applications as high-efficient EMI protection. [ABSTRACT FROM AUTHOR]

A lightweight 3D Ag/CNTs/SBS composite foam was successfully fabricated by a simple freeze-drying process followed by adsorbing and in-situ reducing of silver trifluoroacetate in ethanol solution, which exhibited robust mechanical–electrical performance and high EMI shielding performance due to the synergistic contribution of the CNTs with ultra-high aspect ratio inside the SBS matrix and Ag NPs partially embedded in the superficial surface of the SBS foam skeleton. [Display omitted] • Lightweight Ag/CNTs/SBS foam was fabricated by freeze-drying and in-situ reduction. • CNTs and partially embedded Ag NPs endow the foam with excellent properties. • The foam exhibits high EMI SE of 91 dB at 4 mm in the X band. • The foam possesses enhanced EMI SE value after the cyclic compressions. The porous conductive polymer composites have received great attention owing to their superiority of being utilized in electromagnetic interference (EMI) shielding applications. Herein, lightweight and highly compressible conductive composite foam composed of poly(styrene- block -butadiene- block -styrene) (SBS) polymer matrix, carbon nanotubes (CNTs) and silver nanoparticles (Ag NPs) is fabricated by freeze-drying technology, silver precursor absorption and in-situ reduction process. Three-dimensional CNTs conductive network and partially embedded Ag NPs synergistically endow the foam with excellent mechanical, electrical and EMI shielding performance. The flexible 8Ag/4CNTs/10SBS composite foam with a low density of 0.42 g/cm3 exhibits moderate compressive strength of 169.2 kPa at strain of 50%, remarkable conductivity of 753 S/m, and prominent EMI shielding effectiveness (SE) value of around 91 dB in the electromagnetic wave frequency range of 8.2–12.5 GHz. In addition, the 4Ag/4CNTs/10SBS composite foam exhibits robust mechanical–electrical property upon 1000 compression-release cycles at strain of 50%, and its SE value increased by about 33% compared with the initial state after the cyclic compression test. These results suggest that the Ag/CNTs/SBS foams possess promising potential to be used as lightweight, flexible, and high-performance EMI shielding materials in modern electronic devices. [ABSTRACT FROM AUTHOR]

A lightweight 3D Ag/CNTs/SBS composite foam was successfully fabricated by a simple freeze-drying process followed by adsorbing and in-situ reducing of silver trifluoroacetate in ethanol solution, which exhibited robust mechanical–electrical performance and high EMI shielding performance due to the synergistic contribution of the CNTs with ultra-high aspect ratio inside the SBS matrix and Ag NPs partially embedded in the superficial surface of the SBS foam skeleton. [Display omitted] • Lightweight Ag/CNTs/SBS foam was fabricated by freeze-drying and in-situ reduction. • CNTs and partially embedded Ag NPs endow the foam with excellent properties. • The foam exhibits high EMI SE of 91 dB at 4 mm in the X band. • The foam possesses enhanced EMI SE value after the cyclic compressions. The porous conductive polymer composites have received great attention owing to their superiority of being utilized in electromagnetic interference (EMI) shielding applications. Herein, lightweight and highly compressible conductive composite foam composed of poly(styrene- block -butadiene- block -styrene) (SBS) polymer matrix, carbon nanotubes (CNTs) and silver nanoparticles (Ag NPs) is fabricated by freeze-drying technology, silver precursor absorption and in-situ reduction process. Three-dimensional CNTs conductive network and partially embedded Ag NPs synergistically endow the foam with excellent mechanical, electrical and EMI shielding performance. The flexible 8Ag/4CNTs/10SBS composite foam with a low density of 0.42 g/cm3 exhibits moderate compressive strength of 169.2 kPa at strain of 50%, remarkable conductivity of 753 S/m, and prominent EMI shielding effectiveness (SE) value of around 91 dB in the electromagnetic wave frequency range of 8.2–12.5 GHz. In addition, the 4Ag/4CNTs/10SBS composite foam exhibits robust mechanical–electrical property upon 1000 compression-release cycles at strain of 50%, and its SE value increased by about 33% compared with the initial state after the cyclic compression test. These results suggest that the Ag/CNTs/SBS foams possess promising potential to be used as lightweight, flexible, and high-performance EMI shielding materials in modern electronic devices. [ABSTRACT FROM AUTHOR]