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With the booming of telecommunication and microelectronics, it is essential to develop electromagnetic interference (EMI) shielding materials with low reflectivity characteristics to avoid the secondary pollution from electromagnetic waves (EMWs). Herein, we fabricated a series of hierarchical polypyrrole/carbon nanofiber (PPy/CF) composites with multilayer PPy films. The EMI shielding performance can be adjusted by attaching different layered PPy films. The EMI shielding efficiency (SE) of PPy/CF composite films can reach to 74.59 dB with an electrical conductivity of 3.02 × 10–3 S/mm. Moreover, in order to make the composite film have excellent strength and flexibility, we specially designed an acetone-soluble polyimide (PI) resin to encapsulate PPy/CF. After packaging with PI, the composite films are imparted with high flexibility and mechanical properties with the tensile strength and modulus of 4.65 and 153.03 MPa, respectively. Moreover, the resultant PI/PPy/CF composite films also possess favorable Joule heating performance and sensing monitoring. The Joule heating temperature of PI/PPy/CF films reaches 131.0 °C within 15 s when the applied voltage is 5 V. The fabricated composite films are promising for applications in the fields of aerospace, telecommunication, and microelectronic engineering and multifunctional wearable devices. [ABSTRACT FROM AUTHOR]

Lightweight and mechanically strong multifunctional nanocomposites with integrated electromagnetic interference (EMI) shielding and thermal management capacities are urgently required for protection of emerging aerospace, portable smart electronics and telecommunication devices. Herein, the lightweight, mechanically strong and flame-retardant microcellular aramid nanofiber/Ti 3 C 2 T x MXene (ANF/Ti 3 C 2 T x) nanocomposite foams are developed for integrated EMI shielding and thermal management by the feasible hydrogen bonding assembly, vacuum-assisted filtration and thermal treatment strategy using the solid sacrificial templates. Thanks to the synchronous construction of three-dimensional (3D) continuous conductive networks and microcellular structures, the microcellular nanocomposite foams possess low mass density of 0.29 g/cm3, superior EMI shielding effectiveness (EMI SE) of 64.9 dB, and high EMI SE/t of 10970.3 dB cm2/g, as well as outstanding mechanical properties with an improved tensile strength of 16.5 MPa and excellent flame retardancy. Moreover, the microcellular nanocomposite foams show excellent thermal management performances with intelligently tailorable Joule heating temperatures at low voltages and significant working reliability. Therefore, the lightweight, mechanically strong and flame-retardant MXene-based microcellular nanocomposite foams are promising for emerging EMI shielding and thermal management applications in aerospace, portable smart electronics and telecommunication devices. Lightweight, mechanically strong and flame-retardant MXene-based microcellular nanocomposite foams for integrated EMI shielding and thermal management are fabricated via the feasible hydrogen bonding assembly, vacuum-assisted filtration and thermal treatment strategy. [Display omitted] • The highlights include: • Lightweight, mechanically strong and flame-retardant MXene-based microcellular nanocomposite foams are developed. • Superior EMI shielding performances are achieved owing to the continuous conductive networks and microcellular structures. • The microcellular nanocomposite foams show intelligently tailorable thermal management performances with high reliability. [ABSTRACT FROM AUTHOR]

Multifunctional wearable electronic devices based on natural materials are highly desirable for versatile applications of energy conversion, electronic skin and artificial intelligence. Herein, multifunctional wearable silver nanowire decorated leather (AgNW/leather) nanocomposites with hierarchical structures for integrated visual Joule heating, electromagnetic interference (EMI) shielding and piezoresistive sensing are fabricated via the facile vacuum‐assisted filtration process. The AgNWs penetrate the micro‐nanoporous structures in the corium side of leather constructing highly‐efficient conductive networks. The resultant flexible and mechanically strong AgNW/leather nanocomposites exhibit extremely low sheet resistance of 0.8 Ω/sq, superior visual Joule heating temperatures up to 108 °C at low supplied voltage of 2.0 V due to efficient energy conversion, excellent EMI shielding effectiveness (EMI SE) of ≈55 dB and outstanding piezoresistive sensing ability in human motion detection. This work demonstrates the fabrication of multifunctional AgNW/leather nanocomposites for next‐generation wearable electronic devices in energy conversion, electronic skin and artificial intelligence, etc. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding materials are of great importance for modern daily life, military actions and precise instrument protection because of the complex electromagnetic pollution caused by explosive growth of telecommunications and electronics devices. The conductive polymer composites (CPCs) have been proved to be one of the most promising EMI shielding materials both in fundamental research and practical application due to it set of intriguing lightweight, good processability, low density, chemical stability and excellent mechanical properties. Carbon materials (e.g. graphene, carbon nanotubes, carbon fiber, carbon black) based composites have occupied a prominent position in CPCs for EMI shielding. Not only the electromagnetic pollution should be eliminated or solved, but also the pollution coming from the preparation or processing of polymers. In this regard, waterborne polymer/carbon material composites for EMI shielding can meet the demand. Waterborne polymer will affect the EMI SE performance remarkably by improving the interfacial interaction between carbon materials and polymer and further structure designing of the composite. The composite structure forms including homogeneous structures, multilayer structures, segregated structures and porous structures are mainly discussed in details in this review which may inspire the design for more environment-friendly EMI shielding materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding materials with low reflection and excellent microwave absorption characteristics are highly desirable for high-speed electronics devices to attenuate radiated emissions. Herein, we developed a highly absorption dominated composite EMI shielding foams with "honeycomb" structure through chemical foaming and subsequent in situ vapor deposition of polypyrrole (PPy) within polyimide (PI) foams. After the deposition of PPy, the obtained porous PI foams exhibit electrical conductivity of 2.7 × 103 S/m. In addition, the composite foams demonstrate the highest absorption coefficient of 0.8 and EMI shielding efficiency of 41.1 dB with a thickness of 8 mm. Moreover, the optimal reflection loss (RL) of the composite PI/Fe 3 O 4 -20@PPy foam (PF/Fe 3 O 4 -20@PPy) reach up to −31 dB at 6.0 mm and ≤ −10 dB in the whole X band with a thickness of ≥4 mm. Moreover, the 3D porous structure of PI foam and favorable electrical conductivity of in-situ formed PPy film can contribute to the high sensing performance of PI@PPy foam (PF@PPy). This study provides a novel strategy for the development of lightweight, EMI shielding and microwave absorption materials for advanced applications in flexible anti-radiation and stealth devices. [Display omitted] [ABSTRACT FROM AUTHOR]

• MFEA was prepared for strong adhesion, self-healing property and recyclability. • MFEA/AgNWs films realized stretchable, self-healing and recyclable EMI shielding. • MFEA can adhere to other commercial EMI shielding films with conventional methods. Although the electromagnetic interference (EMI) shielding materials have attracted much attention in recent years, it is still a big challenge to develop EMI materials with stretchable, self-healing and recyclable property, realizing reliable usage and avoiding electronic waste. In this paper, we have developed a multifunctional elastomeric adhesive called MFEA, which comprises polydimethylsiloxane, dimethylacetohydrazide/4,4-methylene bis(phenyl isocyanate), and catechol. MFEA exhibits outstanding mechanical performance(3.75 MPa), strong adhesion(1 MPa), self-healing capabilities(91 %), and recyclability. By leveraging its adhesive properties, we can combine MFEA with silver nanowires. The composite MFEA/AgNWs film not only exhibits outstanding performance, including stretchability, self-healing, adhesion, and recyclability, but can also be used to manufacture EMI shielding films with an shielding strength of up to 53.6 dB. Additionally, the composite film exhibits Joule heating behavior, rapidly heating to over 50 ℃ under a 1.5 V and maintaining stability for an extended duration. Moreover, MFEA can be used to adhere to other commercial EMI shielding films to achieve desired functionalities using conventional methods. This approach provides a universal, convenient, and rapid strategy for preparing flexible electronic materials with various functionalities. [ABSTRACT FROM AUTHOR]

• EMI SE of films can reach 87 dB with extremely low SE R of 6.0 dB at only ~1.0 mm. • Film present outstanding flexibility, mechanical properties and Joule heating performances. • Flexible CF@NiCo/PI films with outstanding impedance matching. The electromagnetic interference (EMI) shielding materials with low reflection characteristics are highly desirable for integrated communication and microelectronics systems to shield EM waves and their secondary pollution. In this study, the EMI shielding materials with outstanding absorption performance were fabricated via the two-step pyrolysis and followed by vacuum assisted filtration approach. The chopped carbon fibers (CFs) wrapped with NiCo 2 O 4 nanowire arrays (CF@NiCo 2 O 4) were prepared by the hydrothermal reaction initially. After annealing, the NiCo 2 O 4 nanowires transformed into NiCo alloy nanoparticles and evenly embedded in the CFs, endowing the CF@NiCo composites with efficient magnetic loss and dielectric loss capacity. After vacuum filtration and encapsulation with polyimide, the obtained flexible CF@NiCo/polyimide composite film displays superior EMI shielding effectiveness of 87 dB with a thickness of only 1.08 mm. Particularly, the composite film exhibits extremely low SE R characteristics of ~6 dB, which surpasses those of most previously reported composites materials with similar thickness. In addition, the composite films present outstanding flexibility, mechanical properties and Joule heating performances. Therefore, the prepared flexible composite films have broad prospect for EMI shielding and thermal management applications in advanced microelectronic systems. [ABSTRACT FROM AUTHOR]

Developing ultrathin, lightweight, flexible and efficient electromagnetic interference (EMI) shielding materials is still a long-standing issue. Herein, a series of biomass derived carbon composite films with superior EMI shielding performance are reported. The cotton derived carbon fabric wrapped with CoFe alloy nanoparticles (CCF@CoFe) was prepared by pyrolysis at temperature of 600–800 °C and subsequently encapsulated by polyimide (PI) resin to obtain the CCF@CoFe/PI films. The prepared composite films present favorable flexibility, remarkable tensile strength of ~10 MPa and exceptional EMI shielding efficiency of ~32 dB over the X-band with the thickness of 0.16 mm. In addition, the EMI shielding performance of the composite films can be adjusted by changing the CoFe loading content and pyrolysis temperature, and an EMI shielding efficiency of ~62 dB is achieved by stacking 6 layers of nanocomposite films, shielding 99.999937% of incident electromagnetic waves with thickness of only 0.98 mm. In view of excellent comprehensive properties, this ultrathin and low-cost biomass derived films are highly promising materials for EMI shielding in practical applications. [ABSTRACT FROM AUTHOR]