Electromagnetic Interference Shielding Film Research Articles

Asymmetric and mechanically enhanced MOF derived magnetic carbon-MXene/cellulose nanofiber films for electromagnetic interference shielding and electrothermal/photothermal conversion

The prosperity of wearable and microelectronic devices tremendously facilitates to exploit thin and flexible composite films with multifunction. Free-standing MXene films have aroused considerable interest in the fields of electromagnetic interference (EMI) shielding and thermal management because of brilliant electrical conductivity, distinctive layered architecture and remarkable localized surface plasmon resonance effect. Nevertheless, the inferior mechanical strength and potential performance degradation in humid environments seriously constrain their practical applications. In this regard, robust and multifunctional CoNi-MOF-74 derived magnetic carbon/cellulose nanofibers (CNF)-MXene/CNF composite films with Janus architecture were successfully constructed via two-step vacuum-assisted filtration technology. The rational arrangement of functional fillers effectively improves the impedance matching, promoting the incident electromagnetic waves to enter the films for consumption. Constructing double-layered structure could induce the generation of “absorption-reflection-reabsorption” dissipation manner, dramatically enhancing EMI shielding performance. The bi-layered magnetic carbon/CNF-MXene/CNF composite membranes (0.1 mm in thickness) realize a fascinating EMI shielding effectiveness of 68.86 dB and a superior absorption efficiency of 58.82 dB. Meanwhile, the brilliant conductivity and significant localized surface plasmon resonance effect of MXene/CNF layer endow the composite films with excellent electrothermal/photothermal conversion capability, greatly broadening application prospects. The steady temperature of the composite films is as high as 112.9 °C within 10 s under the low driven voltage of 3.0 V and the saturation temperature reaches up to 154.2 °C within 15 s at the light intensity of 1500 W/m2, respectively. Moreover, the plentiful hydrogen bonding interaction and compact interfacial combination jointly enable the composite films to possess robust mechanical flexibility, satisfying the demands in practice. This work supplies a prospective guidance for preparing flexible and multifunctional composite films with Janus architecture, revealing great application potential in wearable and microelectronic devices even under harsh conditions.

Ultrathin and highly flexible layered silver nanowires/carboxymethyl cellulose nanofiber nanocomposite films for electromagnetic interference shielding

Lightweight, flexible, efficient and easy-to-manufacture electromagnetic interference (EMI) shielding materials are in urgent demand in the communications industry, artificial intelligence and wearable electronics. Based on the large size difference between one-dimensional carboxymethyl cellulose nanofibers (CMC) and large-diameter silver nanowires (AgNWs), layered AgNWs/CMC nanocomposite films with large effective thickness, and high conductivity were first prepared by a simple one-step vacuum filtration self-assembly technique. The unique layered structure of the AgNWs/CMC nanocomposite film significantly enhances the conductive pathways within the film, endowing it excellent EMI shielding performance. The results show that the conductivity of the ultra-thin film with a thickness of 20 μm is 3.72 × 106 S/m, and the EMI SE in the X-band is 87.7 dB, which can effectively shield electromagnetic signals in mobile communications. Furthermore, the AgNWs/CMCs nanocomposite films exhibit excellent thermal management performance, which can be heated to 100–180 °C within 10 s at a low voltage of 1.5 V. In particular, this nanocomposite film with a new layered structure provides a noval preparation idea for future EMI shielding materials and wearable heating devices.

Conductive water-based graphene suspension for electromagnetic interference shielding via spray coating on SiP module

Conductive inks have been widely used to develop electronic devices, such as sensors, RFID antennas, and transistors. Electronic utilization is a coating that forms conductive films for electromagnetic interference shielding (EMI Shielding). This process also can be employed to cover electronic modules called System in Package (SiP). A technology known as conformal shielding utilizes spray coating with metallic inks to form a conductive layer over the SiP. Traditionally, copper or silver inks have been the primary materials employed due to their high electrical conductivity. Conversely, these metallic inks are associated with significant costs, environmental impacts, and complex production methods. In this context, water-based graphene dispersion could be an alternative to EMI Shielding for electronic chips. Graphene is attractive due to its excellent electrical and thermal properties, reduced cost, and being an environmentally friendly material. In this study, a water-based graphene suspension was developed and applied via spray coating to form films for electromagnetic shielding. The graphene dispersion in water utilized Carboxymethyl cellulose (CMC). Characterizations of the graphene suspension, including morphology, particle size distribution, and chemical analysis, were conducted. The resistivity of the resulting films and their shielding effectiveness (SE) were measured. Electronic chip modules were painted to assess coverage. The study demonstrated the successful formulation of a stable water-graphene suspension exhibiting favorable electrical resistivity (2.8 × 10−2 Ω.cm) after drying at 300 °C for 1 h. The resulting film achieved a shielding effectiveness of −9 dB at 1.0 GHz. Graphene film completely covered the electronic chips, indicating an alternative conformal shielding.

Ultrafine Aramid Nanofiber-Assisted Large-Area Dense Stacking of MXene Films for Electromagnetic Interference Shielding and Multisource Thermal Conversion.

Polymers are often used as adhesives to improve the mechanical properties of flexible electromagnetic interference (EMI) shielding layered films, but the introduction of these insulating adhesives inevitably reduces the EMI performance. Herein, ultrafine aramid nanofibers (UANF) with a diameter of only 2.44 nm were used as the binder to effectively infiltrate and minimize the insulating gaps in MXene films, for balancing the EMI shielding and mechanical properties. Combining the evaporation-induced scalable assembly assisted by blade coating, flexible large-scale MXene/UANF films with highly aligned and compact MXene stacking are successfully fabricated. Compared with the conventional ANF with a larger diameter of 7.05 nm, the UANF-reinforced MXene film exhibits a "brick-mortar" structure with higher orientation and compacter stacking MXene nanosheets, thus showing the higher mechanical properties, electrical conductivity, and EMI shielding performance. By optimizing MXene content, the MXene/UANF film can achieve the optimal tensile strength of 156.9 MPa, a toughness of 2.9 MJ m-3, satisfactory EMI shielding effectiveness (EMI SE) of 40.7 dB, and specific EMI SE (SSE/t) of 22782.4 dB cm2/g). Moreover, the composite film exhibits multisource thermal conversion functions including Joule heating and photothermal conversion. Therefore, the multifunctional MXene/UANF EMI shielding film with flexibility, foldability, and robust mechanical properties shows the practical potential in complex application environments.

Oxhide gelatin-regulated aramid nanofiber/liquid metal films with sandwiched structure for electromagnetic interference shielding

Liquid metal (LM) based electromagnetic interference (EMI) shielding materials with high conductivity and continuous deformation capacity are important needs for meeting modern advanced electronic equipment. However, an independent free-standing film with LM is difficult to achieve due to its unique fluidity properties. Here, a simple alternating filtration film-forming method was utilized to orderly construct a sandwiched EMI shielding film with LM stabilized by bio-based oxhide gelatin (gel) as the intermediate conductive layer, and two films of aramid nanofibers/oxhide gel (ANF/gel) as the external insulating protective layers. This design not only prevents LM from being exposed to environmental conditions, but also reduces the risk of chemical corrosion in practical applications. Under optimal LM addition conditions, the sandwiched film (0.3-3 L) exhibited better EMI shielding performance of 50.4 dB in the X-band than the blended film (0.7 dB), as well as excellent mechanical properties (tensile strength of 65.8 MPa, strain 8.6 %). More importantly, the sandwiched film still maintained reliable EMI shielding performance after being experienced largely physical deformation. This study provides a new solution for preparing LM-based EMI shielding composites, and is expected to arouse pursuit of high EMI shielding effects of bio-based gel while also paying attention to their safety.

Transparent electromagnetic interference shielding materials using MXene

AbstractWith the rapid advancement of terahertz technologies, electromagnetic interference (EMI) shielding materials are needed to ensure secure electromagnetic environments. Enormous efforts have been devoted to achieving highly efficient EMI shielding films by enhancing flexibility, lightweight, mechanical robustness, and high shielding efficiency. However, the consideration of the optical properties of these shielding materials is still in its infancy. By incorporating transparency, visual information from protected systems can be preserved for monitoring interior working conditions, and the optical imperceptibility allows nonoffensive and easy cover of shielding materials for both device and biology. There are many materials that can be applied to transparent EMI shields. In particular, two‐dimensional transition metal carbide/nitrides (MXenes), possessing the advantages of superior conductivity, optical properties, favorable flexibility, and facile processibility, have become a great candidate. This work reviews the recent research on developing highly efficient and optically transparent EMI shields in a comprehensive way. Materials from MXenes, indium tin oxide, metal, carbon, and conductive polymers are covered, with a focus on the employment of MXene‐based composites in transparent EMI shielding. The prospects and challenges for the future development of MXene‐based transparent EMI shields are discussed. This work aims to promote the development of high‐performance, optically transparent EMI shields for broader applications by leveraging MXenes.

Jujube-cake inspired lightweight and flexible MXene/liquid metal/bacterial cellulose electromagnetic interference shielding film with excellent Joule heating and thermal conductivity

The modern 5G communication electronics and systems require lightweight and flexible films that have superior electromagnetic interference (EMI) shielding performance as well as high thermal conductivity. This work reports a facile “one-pot” synthesis strategy to create EMI shielding films with a structure inspired by “jujube cake”. The two-dimensional Ti3C2Tx MXene nanosheets were combined with one-dimensional bacterial cellulose (BC) to form a mechanically entangled supporting framework resembling the structure of a “sponge cake”, wherein zero-dimensional liquid metal (LM) droplets like “jujubes” were ingeniously introduced. A series of multifunctional Ti3C2Tx/LM/BC (TLB) EMI shielding films with highly efficient conductive networks and complete thermal conductivity pathways were prepared through a simple, eco-friendly and highly scalable fabrication process involving vacuum-assisted filtration and hot pressing. Such ultrathin (18 μm) and lightweight (0.63 g cm−3) TLB composite film demonstrates an outstanding specific SE (SSE/t) of 21695.8 dB cm2 g−1. Meanwhile, it exhibits a remarkable in-plane thermal conductivity of 10.44 W m−1 K−1 and exceptional Joule heat performance from room temperature to 95 °C at 3.0 V in seconds. These attractive properties and scalable fabrication of TLB composite film showcase its potential in the realm of flexible electronics, particularly for applications pertaining to EMI shielding protection, electromagnetic compatibility and thermal management.

Flexible conductive polymer composite film with sandwich-like structure for ultra-efficient and high-stability electromagnetic interference shielding

Flexible electromagnetic interference (EMI) shielding films with the merits of light-weight, flexibility, and high EMI shielding performance are the essential materials for the consumer electronics and communication products. Herein, we construct a hybrid conductive network based on the electrospinning thermoplastic polyurethane (TPU) film loaded with different dimensional conductive fillers, including 0D FeCl3, 1D carbon nanotube (CNT) and 2D graphene nanosheet (GN) to achieve a flexible, light-weight, and ultra-efficient EMI shielding composite film. In specific, the electrospinning porous TPU film is firstly anchored by CNTs assisted by ultrasound to generate the porous TPU/CNT film. Thereafter, the as-prepared porous TPU/CNT film is loaded a GN/CNT/FeCl3 layer by vacuum-assisted filtration to generate a double-layer GN/CNT/FeCl3@TPU/CNT film. Finally, another porous TPU/CNT film is sealed onto the GN/CNT/FeCl3@TPU/CNT film by hot-pressing, which fabricates a sandwiched TPU/CNT@GN/CNT/FeCl3@TPU/CNT composite film. It is interesting to note that the composite film possesses the ultrahigh EMI shielding value (56.0 dB at 10.0 GHz) in the X-band (8.2–12.4 GHz) with high flexibility, excellent mechanical properties, long-term durability (acid-base environment resistance and stability after 1000 bends), as well as high thermal conductivity (6.53 W/(m.K)). This work proposes a simple but efficiency strategy to design the flexible EMI shielding film with ultra-high performance and outstanding durability.

Absorption‐Dominant Electromagnetic Interference (EMI) Shielding across Multiple mmWave Bands Using Conductive Patterned Magnetic Composite and Double‐Walled Carbon Nanotube Film

AbstractThe revolution of millimeter‐wave (mmWave) technologies is prompting a need for absorption‐dominant EMI shielding materials. While conventional shielding materials struggle in the mmWave spectrum due to their reflective nature, this study introduces a novel EMI shielding film with ultralow reflection (<0.05 dB or 1.5%), ultrahigh absorption (>70 dB or 98.5%), and superior shielding (>70 dB or 99.99999%) across triple mmWave frequency bands with a thickness of 400 µm. By integrating a magnetic composite layer (MCL), a conductive patterned grid (CPG), and a double‐walled carbon nanotube film (DWCNTF), specific resonant frequencies of electromagnetic waves are transmitted into the film with minimized reflection, and trapped and dissipated between the CPG and the DWCNTF. The design factors for resonant frequencies, such as the CPG geometry and the MCL refractive index, are systematically investigated based on electromagnetic wave propagation theories. This innovative approach presents a promising solution for effective mmWave EMI shielding materials, with implications for mobile communication, radar systems, and wireless gigabit communication.

Shear-Induced Fabrication of Cellulose Nanofibril/Liquid Metal Nanocomposite Films for Flexible Electromagnetic Interference Shielding and Thermal Management.

To address electromagnetic interference (EMI) pollution in modern society, the development of ultrathin, high-performance, and highly stable EMI shielding materials is highly desired. Liquid metal (LM) based conductive materials have received enormous amounts of attention. However, the processing approach of LM/polymer composites represents great challenges due to the high surface tension and cohesive energy of LMs. In this study, we develop a universal one-step fabrication strategy to directly process composites containing LMs and cellulose nanofibrils (CNFs) and successfully fabricate the ultrathin, flexible, and stable EMI shielding films with an average specific EMI shielding efficiency (EMI SE) value of 429 dB/mm and small thickness of only 70 μm in the wide frequency range of 8.2-18 GHz. In addition, the resulting films also exhibit excellent mechanical performance and flexibility, which endow the film with the ability to withstand repeated folding, bending, and folding into complex shapes without producing cracks or fractures. Besides, the resulting films display excellent thermal conductivity with a λ of 4.90 W/(m K) and an α of 3.17 mm2/s. Thus, the presented approach shows great potential in fabricating advanced materials for EMI shielding applications.

One-step aerosol synthesis of iron nanoparticles coated single-walled carbon nanotubes (Fe@SWCNT) for multifunctional composite textiles with electromagnetic interference shielding properties

Single-walled carbon nanotubes (SWCNTs) based nanocomposites demonstrate remarkable electromagnetic interference (EMI) shielding potential. However, the efficient and rapid fabrication of SWCNT-based nanocomposite remains a technical challenge. This study successfully one-step synthesizes iron (Fe) nanoparticle-enriched SWCNTs (Fe@SWCNT) using the floating catalyst chemical vapor deposition (FCCVD) method in the aerosol phase. The aerosol-synthesized Fe@SWCNTs were directly integrated with carbon cloth (CC) and polydimethylsiloxane (PDMS) to develop a compelling nanocomposite film for multifunctional EMI shielding. The composite film exhibits exceptional shielding effectiveness of 50.2 dB in the X-band (8.2–12.4 GHz) with absolute shielding effectiveness (SSEt) of 3279.3 dB cm²/g. Notably, the film also displays rapid and uniform electrical heating at low voltages, reaching a temperature of 110.4 °C under a 1.0 V. Overall, this study reveals the potential applications of multifunctional textiles in fields such as EMI shielding, hydrophobicity, and thermal management.

Flexible, Transparent and Conductive Metal Mesh Films with Ultra-High FoM for Stretchable Heating and Electromagnetic Interference Shielding.

Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference (EMI) shielding, achieving a flexible EMI shielding film, while maintaining a high transmittance remains a significant challenge. Herein, a flexible, transparent, and conductive copper (Cu) metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating technique. The Cu mesh film shows an ultra-low sheet resistance (0.18 Ω □-1), high transmittance (85.8%@550nm), and ultra-high figure of merit (> 13,000). It also has satisfactory stretchability and mechanical stability, with a resistance increases of only 1.3% after 1,000 bending cycles. As a stretchable heater (ε > 30%), the saturation temperature of the film can reach over 110°C within 60s at 1.00V applied voltage. Moreover, the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4dB in the X-band at the thickness of 2.5μm. As a demonstration, it is used as a transparent window for shielding the wireless communication electromagnetic waves. Therefore, the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.

Flexible MXene-based Janus film with superior heat dissipation capability for ultra-efficient electromagnetic interference shielding and Joule heating

The incorporation of polymers into MXene-based functional materials has been proven to be an effective strategy for improving their flexibility and mechanical properties. However, insulating polymers inevitably sacrifice the conductivity of MXene, resulting in a deterioration of electromagnetic interference (EMI) shielding performance. In this work, inspired by Janus structure, an asymmetric flexible film composed of the carboxylated styrene-butadiene rubber (XSBR) with magnetic boron nitride nanosheets (mBNNS) layer and the MXene layer is developed through a casting plus spraying approach. The resulting mBNNS/XSBR@MXene (BXM) Janus film demonstrates the characteristic of “one side insulation, one side conductivity”, with the conductivity of 2746 S cm−1 on the MXene side and surface resistivity of 4.9 × 1013 Ω on the mBNNS/XSBR side. Profit from the designed Janus architecture, the EMI shielding effectiveness and in-plane thermal conductivity of the BXM Janus film reach 74.55 dB and 8.45 W m−1 K−1 when the total mass fraction of mBNNS and MXene is 50 wt%, which is 148 % and 43.46 % higher than that of the BXM blend film without Janus structure. Moreover, the BXM Janus film exhibits low applied voltage (∼3.0 V) driven Joule heating performance with a response time of less than 10 s, a saturation temperature of 133.7 °C, and long-term steady reliability. Meanwhile, the BXM Janus film possesses good mechanical properties and excellent EMI shielding stability. Therefore, this work provides an effective strategy to fabricate flexible MXene-based multifunctional film for EMI shielding, heat dissipation, and thermal management applications.

Self‐Destructible Electromagnetic Interference Shielding Films

AbstractIn response to the increasing utilization of communication technology, there is a growing need for electromagnetic interference (EMI) shielding materials to adapt to diverse application scenarios. In this study, the self‐destructible EMI shielding films (SEFs) that possess the unique capability to reduce conductivity and shielding efficiency through temperature elevation are introduced. The SEFs effectively fulfill the requirement of triggering EMI shielding failure under specific conditions, which can be achieved by simply spraying a mixture of thermally expandable microspheres (TEMs), conductive fillers, and resin substrates. The segregated structures resulting from the incorporation of TEMs confer exceptional electrical conductivity and superior EMI shielding performance at low conductive filler content. When the ambient temperature surpasses the glass transition temperature of the TEM shell, the thermally expandable characteristics cause a disruption in the conductive path of the SEFs, leading to a significant decline in shielding effectiveness. Additionally, the SEFs exhibit outstanding Joule heating effects (90 °C) at low voltage (1.5 V) within a brief time frame (10 s). Importantly, when employed as Joule heaters, the SEFs possess an intrinsic safety mechanism that automatically ceases operation in the event of circuit overload, thus minimizing any potential risks.

Silver nanowires/cellulose flexible transparent conductive films for electromagnetic interference shielding and electrothermal conversion.

Currently, electromagnetic shielding materials need to meet the characteristics of lightweight, high transmittance, and robust conductivity. Silver nanowires (AgNWs) have progressively found applications in recent years owing to their excellent aspect ratio, conductivity, and flexibility. The properties of AgNWs vary with different aspect ratios, and the length and diameter of AgNWs often exert diverse influences on the photoelectric properties of conductive films. In this study, we combined AgNWs with hydroxypropyl methylcellulose (HPMC) and employed a directional stacking arrangement method to apply AgNWs onto the PET substrate, investigating the properties of four distinct aspect ratios of AgNWs (1000, 750, 625, and 531). Ultimately, the prepared four films achieved electromagnetic shielding capabilities ranging from 26.6 dB to 32.8 dB, with a transmittance range of 89.8% to 94.6%, showing excellent electromagnetic shielding properties. Moreover, the prepared films showed an exceedingly low roughness value (RMS = 7.07 nm), remarkable flexibility, and superior oxidation resistance with the facilitation of HPMC. The films also showed exceptional electrothermal conversion prowess, achieving saturation temperature within a mere 8 seconds, thereby displaying a rapid thermal response. Furthermore, when a voltage of 4 V was applied, the temperature of the thin film remained essentially constant for a duration of 2500 seconds, highlighting its admirable thermal stability, which is of great significance for the development of flexible and transparent electromagnetic shielding materials in the future.

Comparative Effects of Hydrazine and Thermal Reduction Methods on Electromagnetic Interference Shielding Characteristics in Foamed Titanium Carbonitride MXene Films.

The urgent need for the development of micro-thin shields against electromagnetic interference (EMI) has sparked interest in MXene materials owing to their metallic electrical conductivity and ease of film processing. Meanwhile, postprocessing treatments can potentially exert profound impacts on their shielding effectiveness (SE). This work comprehensively compares two reduction methods, hydrazine versus thermal, to fabricate foamed titanium carbonitride (Ti3CNTx) MXene films for efficient EMI shielding. Upon treatment of ≈ 100µm-thick MXene films, gaseous transformations of oxygen-containing surface groups induce highly porous structures (up to ≈ 74.0% porosity). The controlled application of hydrazine and heat allows precise regulation of the reduction processes, enabling tailored control over the morphology, thickness, chemistry, and electrical properties of the MXene films. Accordingly, the EMI SE values are theoretically and experimentally determined. The treated MXene films exhibit significantly enhanced SE values compared to the pristine MXene film (≈ 52.2dB), with ≈ 38% and ≈ 83% maximum improvements for the hydrazine and heat-treated samples, respectively. Particularly, heat treatment is more effective in terms of this enhancement such that an SE of 118.4dB is achieved at 14.3GHz, unprecedented for synthetic materials. Overall, the findings of this work hold significant practical implications for advancing high-performance, non-metallic EMI shielding materials.

Unleashing multifunctionality: Janus-structured flexible CNT-based composite film with enduring superhydrophobicity and excellent electromagnetic interference shielding

Versatile electromagnetic interference (EMI) shielding films are crucial for electronics and wearables. We acid-functionalize CNTs and load them with Fe3O4, and then fabricate Janus-structured Fe3O4@CNTs/ bacterial cellulose (BC)/ silver nanowires (AgNWs) composite films using layer-by-layer vacuum filtration and hot pressing. Benefiting from the rational regulation of component proportions and the design of a Janus structure, the composite film with a thickness of only 90 μm exhibits outstanding shielding effectiveness (SE) of 68.68 dB in the X-band, owing to the mechanism of absorption-reflection-reabsorption. Moreover, 1H,1H,2H,2H-Perfluorodecyltrimethoxysilane, and ethyl orthosilicate are utilized to synthesize fluoroalkyl-grafted silica nanoparticles (F-SiO2) and coated onto the film’s upper surface using spray technique, rendering it superhydrophobicity (150° <WCA < 160°), oleophobicity (CA ≈110°), and self-cleaning. Excitingly, the highly efficient Joule heating properties (rise to 107.2 °C within 30 s with 1.0 V) of the film (Fe3O4@CNTs/ BC/ F-SiO2/ AgNWs), combine with its superhydrophobicity, provide additional de-icing capabilities. The practical significance lies in the robust interlayer adhesion and intralayer entanglement, which endow the film with remarkable flexibility and sufficient tensile strength (33.5 MPa), ensuring its applicability in complex scenarios. This research presents an innovative and intriguing material combination and offers an efficient manufacturing strategy for EMI shielding films. It is highly suitable for outdoor portable or wearable devices and holds remarkable application potential in damp/ freezing environments.

Flexible and hydrophobic polyimide/MXene-POSS nanocomposite films for electromagnetic interference shielding

A strategy for fabricating polyimide(PI)/MXene-POSS nanocomposite films with excellent electromagnetic interference (EMI) shielding, water resistance, and flame retardance was developed. Herein, the hydrophobic MXene-POSS hybrid was successfully prepared by modifying MXene with polyhedral oligomeric silsesquioxane (POSS). On the one hand, MXene-POSS has good compatibility with PI, so that uniform films can be prepared; on the other hand, the prepared composite films have hydrophobic properties, improving their application in extreme environments. The nanocomposite film with 20 wt% MXene-POSS content achieved a desirable EMI shielding performance of 12.7 dB. In addition, the PI/MXene-POSS nanocomposite also exhibited excellent fire resistance. Moreover, due to the hydrophobic properties of the PI/MXene-POSS-20 % nanocomposite, the water uptake of the PI/MXene-POSS-20 % nanocomposite film was approximately 1.4 % under 70 % relative humidity. The PI/MXene-POSS nanocomposite film demonstrates reasonable EMI shielding performance with high stability and durability, which has the potential for broad applications in electronic devices designed for use in extreme outdoor environments.

Composite polymeric film for stretchable, self-healing, recyclable EMI shielding and Joule heating

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.

All-in-one integrated flexible PE@PET/MXene films for high-performance electromagnetic shields with self-reinforced conductivity and mechanical properties

MXene-based composites are deemed as promising electromagnetic interference (EMI) shielding candidates to address the rapidly increasing electromagnetic interference and radiation concerns. However, developing high-performance flexible polymer-MXene composites with excellent EMI shielding efficiency (EMI SE), good mechanical properties and superior serving stability is a significant challenge. Herein, a type of all-in-one designed lightweight, thin, ultra-flexible PE@PET/MXene films are developed using a novel PE@PET nonwoven fabric (NWF) as the supporter. A mussel-inspired polydopamine modification facilitates the uniform loading of MXene, achieving high electrical conductivity of the resultant PE@PET/MXene films. A simple hot-pressing process is then employed to melt the sheath PE component of PE@PET to serve as a “self-glue” in adhering and wrapping the loaded MXene nanosheets, while maintaining the core PET fibers as the internal “steel” skeleton. As such, the resultant PE@PET/MXene films exhibit multiple self-enhancement metrics involving high mechanical strength, good electrical conductivity, robust serving stability, and superior EMI shielding performance. An optimized PE@PET/MXene film can preserve an excellent EMI SE of 50.44 dB and an ultra-high absolute shielding effectiveness (SSE/t) of 10606 dB cm2 g−1. The versatility of PE@PET/MXene EMI shielding films is further indicated by integrating the flame-retardant additives to endow its flame-retardant function, demonstrating excellent versability and expandability.