Extreme environment-bearable polyimide film with a three-dimensional Ag microfiber conductive network for ultrahigh electromagnetic interference shielding

Abstract

To ensure the normal operation of electronic equipment and provide protection from electromagnetic radiation, polymer-based electromagnetic interference (EMI) shielding materials are widely developed in the electronic communication field. However, it remains a challenge to prepare EMI shielding composites with ultrahigh EMI shielding efficiency (EMI SE), low thickness, high durability, and flexibility in harsh environments, such as extremely high or low temperatures in aerospace. In this study, we used blow spinning and compression molding to construct a highly efficient EMI shielding polyimide (PI) film containing a Ag microfiber sponge (AgMS). The three-dimensional (3D) conductive network constructed by 28-vol% AgMS endows the AgMS/PI film with very high electrical conductivity of 4.5 × 10 6 S m −1 and an EMI SE of up to 90.6 dB, at only 20-μm thickness. Even after working at −196 or 250°C for 120 h, the excellent EMI shielding performance is maintained, with EMI SE retention higher than 85.1 dB. Furthermore, AgMS/PI film exhibits outstanding thermal management performance, achieving a high saturation temperature of 200.2°C at very low supplied voltage (1.1 V), revealing a quick response time (3.1 s), excellent cyclic heating stability, and outstanding reliability. These outstanding properties indicate the great potential of AgMS/PI films in the electronic communication field under harsh environments and artificial intelligence.

Eco-Friendly Scalable Manufacturing Silver Transparent Сonductive Mesh and Silver Micro Caps, in One Technological Cycle for Efficient EMI Shielding Materials for 5G Communications

“…Figure 12. T (a) and R (b) spectra of silver micro caps films in the K band; Comparative dependence of SE on the thickness of silver micro caps films (M-100) with promising literature results:Ag flakes/ WPU composite films[73]; Cu nanosheets films[4]; Ag flakes/ WPU composite films[74]; Ag nanofibers films[75]; Ag microfibers/ PI composite film[76]; Densified SWCNT films[77]; Carbonfabric/ Ag/ WPU composite[78]; Ti3C2Tx films[11]; Ti3C2Tx/ CNT hybrid films[79] (c).…”

“…This fact makes silver micro caps films interesting objects for study in order to obtain shielding materials operating in a wide frequency range, including 5 G. To confirm the above assumptions, we study the spectral characteristics of silver micro caps films M-100 in a wide frequency range. Figure 12 shows the spectral dependences of the transmittance (T) (Figure 12a) and reflectance (R) (Figure 12b) for silver micro caps films M-100 of various surface density in the K range (18-26.5 GHz) (Figure 12b) [73]; Cu nanosheets films [4]; Ag flakes/ WPU composite films [74]; Ag nanofibers films [75]; Ag microfibers/ PI composite film [76]; Densified SWCNT films [77]; Carbonfabric/ Ag/ WPU composite [78]; Ti3C2Tx films [11]; Ti3C2Tx/ CNT hybrid films [79]…”

A flexible precontact CNT-Al2O3 fiber sensor resistant to extreme temperatures

“…In all the nanoscale structures of ceramic materials, the one-dimensional structure with a large aspect ratio, with the advantages of high surface area, low density, excellent mechanical properties and multifunctionality, is one of the main structures of ceramic materials with flexibility. Among the various preparation processes, electrospinning, 17–19 blow spinning, 16,20 chemical vapor deposition (CVD) 21,22 and atomic layer deposition (ALD) 23,24 are suitable options to accomplish this task. For example, a large-area flexible TiO 2 nanofiber network is prepared by the extended electrospinning method, and the flexible pressure sensor based on the ceramic network can withstand high temperatures up to 370 °C.…”

“…Among the various preparation processes, electrospinning, [17][18][19] blow spinning, 16,20 chemical vapor deposition (CVD) 21,22 and atomic layer deposition (ALD) 23,24 are suitable options to accomplish this task. For example, a large-area flexible TiO 2 nanofiber network is prepared by the extended electrospinning method, and the flexible pressure sensor based on the ceramic network can withstand high temperatures up to 370 °C.…”

Flexible Polyimide Foams Coated with Graphene Nanoplatelets/Fe3O4 for Absorption-Dominated Electromagnetic Interference Shielding, Broad-Band Microwave Absorption, and Sensor Applications

“…Polyimide (PI) has high-temperature resistance (>400 °C), outstanding mechanical properties, and chemical resistance, which is highly desirable for framework materials. − Moreover, the PI foam is a high-performance polymer foam with excellent designability, high thermal insulation and stability. ,− Benefiting from the three-dimensional (3D) porous structure of the PI foams and multiple interfaces, it is beneficial to design high performance EMI shielding materials by reflecting EW repeatedly and attenuating EW effectively. ,, …”