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The strategy of incorporating polymers into MXene-based functional materials has been widely used to improve their mechanical properties, however with inevitable sacrifice of their electrical conductivity and electromagnetic interference (EMI) shielding performance. This study demonstrates a facile yet efficient layering structure design to prepare the highly robust and conductive double-layer Janus films comprised of independent aramid nanofiber (ANF) and Ti 3 C 2 T x MXene/poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) layers. The ANF layer serves to provide good mechanical stability, whilst the MXene/PEDOT:PSS layer ensures excellent electrical conductivity. Doping PEDOT:PSS into the MXene layer enhances the interfacial bonding strength between the MXene and ANF layers and improves the hydrophobicity and water/oxidation resistance of MXene layer. The resultant ANF/MXene-PEDOT:PSS Janus film with a conductive layer thickness of 4.4 µm was shown to display low sheet resistance (2.18 Ω/sq), good EMI shielding effectiveness (EMI SE of 48.1 dB), high mechanical strength (155.9 MPa), and overall toughness (19.4 MJ/m 3 ). Moreover, the excellent electrical conductivity and light absorption capacity of the MXene-PEDOT:PSS conductive layer mean that these Janus films display multi-source driven heating functions, producing excellent Joule heating (382 °C at 4 V) and photothermal conversion (59.6 °C at 100 mW/m 2 ) properties.

With the rapid development of the electronic industry and wireless communication technology, electromagnetic interference (EMI) or pollution has been increasingly serious. This not only severely endangers the normal operation of electronic equipment but also threatens human health. Therefore, it is urgent to develop high-performance EMI shielding materials. The advent of hydrogel-based materials has given EMI shields a novel option. Hydrogels combined with conductive functional materials have good mechanical flexibility, fatigue durability, and even high stretchability, which are beneficial for a wide range of applications, especially in EMI shielding and some flexible functional devices. Herein, the current progress of hydrogel-based EMI shields was reviewed, in the meanwhile, some novel studies about pore structure design that we believe will help advance the development of hydrogel-based EMI shielding materials were also included. In the outlook, we suggested some promising development directions for the hydrogel-based EMI shields, by which we hope to provide a reference for designing hydrogels with excellent EMI shielding performance and multifunctionalities.

The development of infrared‐radar compatible materials/devices is challenging because the requirements of material properties between infrared and radar stealth are contradictory. Herein, a composite of poly(3, 4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) coated melamine foam is designed to integrate the advantages of the dual materials and the created heterogeneous interface between them. The as‐designed PEDOT:PSS@melamine composite shows excellent mechanical properties, outstanding thermal insulation, and improved thermal infrared stealth performance. The relevant superb radar stealth performance including the minimum reflection loss value of −57.57 dB, the optimum ultra‐wide bandwidth of 10.52 GHz, and the simulation of radar cross section reduction value of 17.68 dB m2, can be achieved. The optimal specific electromagnetic wave absorption performance can reach up as high as 3263.02 dB·cm3 g−1. The average electromagnetic interference shielding effectiveness value can be 30.80 dB. This study provides an approach for the design of high‐performance stealth materials with infrared‐radar compatibility. A high‐performance infrared‐radar compatible stealth composite is fabricated. The actual radar cross‐section performance is rationally simulated via smart computer simulation technology.

Flexible electromagnetic interference (EMI) shielding films with high stability have shown promising prospect in harsh working conditions such as military, communication, and special protection fields. Herein, flexible aramid nanofibers@polypyrrole (ANF@PPy) films with high stability were easily achieved by the in-situ growth of PPy on the surface of ANF and the subsequent pressured-filtration film-forming process. When the amount of pyrrole (Py) monomer is 40 µL, the ANF@PPy (AP40) film exhibited excellent EMI shielding performance with shielding effectiveness (SE) of 41.69 dB, tensile strength of 96.01 MPa, and fracture strain of 21.95% at the thickness of 75.76 µm. Particularly, the anticipated EMI shielding performance can be maintained even after being heated at 200 °C in air, soaked in 3.5% NaCl solution, repeated folding for one million times, or burned directly, indicating superior environmental durability in harsh conditions. Therefore, it is believed that the ANF@PPy films with high stability offer a facile solution for practical protection for high-performance EMI shielding applications.

The rapid improvement in the running speed, transmission efficiency, and power density of miniaturized devices means that multifunctional flexible composites with excellent thermal management capability and high electromagnetic interference (EMI) shielding performance are urgently required. Here, inspired by the fibrous pathways of the human nervous system, a “core-sheath” fibers structured strategy was proposed to prepare thermoplastic polyurethane/polydopamine/carbon nanotube (TPU/PDA/CNT) composites film with thermal management capability and EMI shielding performance. Firstly, TPU@PDA@CNT fibers with CNT shell were prepared by a facile polydopamine-assisted coating on electrospun TPU fibers. Subsequently, TPU/PDA/CNT composites with three-dimensional (3D) fibrous CNT “tracks” are obtained by a hot-pressing process, where CNTs distributed on adjacent fibers are compactly contacted. The fabricated TPU/PDA/CNT composites exhibit a high in-plane thermal conductivity (TC) of 9.6 W/(m·K) at low CNT loading of 7.6 wt.%. In addition, it also presents excellent mechanical properties and excellent EMI shielding effectiveness of 48.3 dB as well as multi-source driven thermal management capabilities. Hence, this study provides a simple yet scalable technique to prepare composites with advanced thermal management and EMI shielding performance to develop new-generation wireless communication technologies and portable intelligent electronic devices.

Electrically conductive porous structures are ideal candidates for lightweight and absorption-dominant electromagnetic interference (EMI) shielding. In this review, we summarize the recent progress in developing porous composites and structures from emerging two-dimensional (2D) graphene and MXene nanosheets for EMI shielding applications. Important properties contributing to various energy loss mechanisms are probed with a critical discussion on their correlations with EMI shielding performance. Technological approaches to constructing bulk porous structures, such as 2D porous films, three-dimensional (3D) aerogels and foams, and hydrogels, are compared to highlight important material and processing parameters required to achieve optimal microstructures. A comprehensive comparison of EMI shielding performance is also carried out to elucidate the effects of different assembly techniques and microstructures. Distinctive multifunctional applications in adaptive EMI shielding, mechanical force attenuation, thermal management, and wearable devices are introduced, underlining the importance of unique compositions and microstructures of porous composites. The process-structure-property relationships established in this review would offer valuable guidance and insights into the design of lightweight EMI shielding materials.

The increasing need for electromagnetic interference (EMI) shielding of electronics in cold environments such as those in aircraft, space exploration, and wearable heaters to avoid hazardous icing conditions or hypothermia requires the development of thin and lightweight EMI shielding materials preferably by absorbing rather than reflecting electromagnetic (EM) waves while also generating heat through energy-efficient electrothermal conversion. However, it is challenging to achieve absorption-dominant EMI shielding and energy-efficient electrothermal heating simultaneously in a thin and lightweight structure. Here, we develop a heterogeneous composite film comprising a porous multi-walled carbon nanotubes (MWCNTs)/bacterial cellulose (BC) film and an aligned MXene/Ag nanowires (NWs) backing via a sequential vacuum filtration process. The porous film contains random conductive networks of MWCNTs with moderate conductivity while the aligned MXene sheets atop Ag NWs network affords high conductivity in the backing, giving rise to graded electrical conductivity for absorption-dominant EMI shielding. The increasing Ag NW coverage leads to significantly increased electrical conductivity without increasing the EM wave reflection as well as the density and thickness of the film, yielding excellent specific EMI shielding effectiveness (> 8500 dB/(g·cm 2 )), low driving voltage for energy-efficient electrothermal heating (163 °C at 2.5 V), and fast response time (60 s) at a low areal density of 0.015 mg/cm 2 . Combining EMI shielding and electrothermal heating, the heterogeneous film developed here are promising contenders for the protection of electronic equipment in low-temperature environment.

The excrescent electromagnetic (EM) radiation exposure in the air threatens human health and electronic equipment due to the abuse of EM waves in wireless telecommunication technology and electronic applications. Consequently, electromagnetic interference (EMI) shielding materials are provided to solve the EM waves pollution problem. In particular, the appearance of one-dimensional (1D) metallic, magnetic, and dielectric nanofillers will extremely reduce the density of EMI composite and enhance EMI protection performance because they can easily assemble to form complete two-dimensional (2D) or three-dimensional (3D) EMI network based on their high aspect ratio, large specific surface area, and additional attenuated sites. This review focuses on the EMI shielding composites with 1D metallic, magnetic, and dielectric nanofillers, which could be constructed in the final form of membrane- or aerogel/sponge-like shielding materials. According to the structural features, 1D metallic, magnetic, and dielectric nanofillers are classified into nanowires, nanorods, nanospindles, nanochains, nanofibers, nanotubes, nanorings, nanocoils, and quasi-one-dimensional (1D) van der Waals materials. Accordingly, the fabricated routes, shielding performances, and EM waves attenuation mechanism of the 1D metallic, magnetic, and dielectric nanofiller-based composites are summarized. It is found that the dominant shielding mechanism of most of the 1D metal-based EMI composites is reflection loss, while that of 1D magnetic and dielectric nanomaterials-based EMI composites is absorption loss caused by interfacial polarization, natural resonance, eddy current, and multiple scattering. Finally, the challenges and prospects of 1D nanofiller-based composites with a tunable architecture and composition are put forward, aiming to give a guideline for the next generation of high-performance EMI shielding materials.

Conductive filler loading in the polymer matrix is a common practice to transform insulative polymers to conducting composites. In case of textiles, the highly promising approach has been coined by virtue of fabricating with conductive adhesive homogeneous coating. The present fabrication approach has been developed by two-stage wet mixing technique including synthesis of silver nanoparticles decorated graphene sheets (rGO/Ag), followed by the preparation of conducting coating by non-ionic polymer adhesive. The novelty lies in the choice of conductive material and coating strategy to make lightweight and flexible smart electronic fabric. In order to protect the radiation pollution from the immense use of electronic devices and gadgets, the coated textiles can be an excellent replacement of other commercially available polymer coatings. The electromagnetic interference (EMI) shielding effectiveness of the prepared coated textile was 27.36 dB in the X band (8.2–12.4 GHz). Besides this it is worth mentioning that our developed coated fabric was enough conductive to light up a series of 57 LEDs with high intensity. Last but not the least this work also reconnoitres bactericidal feature against E. coli.

Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors, electromagnetic shielding, and so on. However, the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical applications. In this work, we developed a synchronous deprotonation-protonation method in the KOH/dimethyl sulfoxide (DMSO) system at room temperature for achieving chitin cross-linked aramid nanofibers (CANFs) rather than chitin nanofibers (ChNFs) and aramid nanofibers (ANFs) separately by using chitin and aramid pulp as raw materials. After freeze-drying process, the cross-linked chitin/aramid nanofibers (CA) aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation strategy. The mechanical stress of CA aerogel was 170 kPa at 80% compressive strain, increased by 750% compared with pure ChNF aerogel. Similarly, the compressibility of CA aerogel was somewhat improved compared to ANF aerogel. The enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was formed. Afterwards, the conductive aerogels with uniform porous structure (CA-M) were successfully obtained by vacuum impregnating CA aerogels in Ti 3 C 2 T x MXene solution, displaying low thermal conductivity (0.01 W/(m·K)), high electromagnetic interference (EMI) shielding effectiveness (SE) (75 dB), flame retardant, and heat insulation. Meanwhile, the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring capabilities. As a result, the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics, EMI shielding, flame retardant, and heat insulation.