Electromagnetic Interference Shielding Film Research Articles

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.

MOF@wood Derived Ultrathin Carbon Composite Film for Electromagnetic Interference Shielding with Effective Absorption and Electrothermal Management

AbstractRecently, there has been a growing demand for ultra‐thin carbonized wood films (CWF) with high shielding efficiency (SE) to replace non‐renewable alternatives. Researchers aim to enhance electromagnetic (EM) wave absorption and improve electromagnetic interference (EMI) SE in CWF materials to reduce secondary pollution from reflected EM waves. In this work, the carbonized wood composite film (CWF/EP/Co) with a thickness of 120 µm through the process of hot‐pressing and carbonizing wood soaked in a mixed solution of water‐borne epoxy (EP) and Co/Zn‐MOF (ZIF‐67/8) is obtained. The CWF/EP/Co film exhibits excellent conductivity (105 S cm−1) and demonstrates an excellent EMI SE (73 dB) at a 200 µm thickness. Remarkably, the specific EMI shielding effectiveness (SSE/t) of CWF/EP/Co films reached 15833.3 dB·cm2·g−1 in the X‐band, making it the highest reported value among all wood‐derived EMI shielding materials. CWF/EP/Co films have a high absorption coefficient (A) of 0.4, indicating their effectiveness in absorbing EM waves. Furthermore, the EMI shielding effect of the large‐scale wallpaper (170 mm×170 mm) is confirmed by finite element analysis. Additionally, the CWF/EP/Co film exhibits good mechanical properties and effective Joule heating performance. This shielding film shows promise in applications such as buildings and smart homes, providing EMI shielding and warming effects.

High-strength, super-tough, and durable nacre-inspired MXene/heterocyclic aramid nanocomposite films for electromagnetic interference shielding and thermal management

High-strength, super-tough, and durable nacre-inspired MXene/heterocyclic aramid nanocomposite films for electromagnetic interference shielding and thermal management

Ferrite-Decorated Ultrathin and Lightweight Carbon Nanotube Film for Electromagnetic Interference Shielding

Ferrite-Decorated Ultrathin and Lightweight Carbon Nanotube Film for Electromagnetic Interference Shielding

Reinforcing and toughening bacterial cellulose/MXene films assisted by interfacial multiple cross-linking for electromagnetic interference shielding and photothermal response

Ultrathin MXene composite films, with their flexibility, metal-level conductivity, and multifunction compatibility, are an ideal choice for electromagnetic interference (EMI) shielding materials in future developments. Nonetheless, the dilemma between electrical conductivity and robustness in these composite films remains a challenge. Herein, an ammonium polyphosphate (APP) assisted interfacial multiple cross-linking strategy, achieved via simple solution blending and filtration, was employed to reinforce and toughen the “brick–mortar” layered MXene/bacterial cellulose (MBCA) films without compromising their conductivity and EMI shielding ability. The introduction of a small amount of APP leads to multiple interfacial interactions between MXene and bacterial cellulose, resulting in significant enhancements in mechanical strength (360.8 MPa), Young's modulus (2.8 GPa), fracture strain (17.3%), and toughness (34.1 MJ/m3). Concurrently, the MBCA film displayed satisfactory conductivity values of 306.7 S/cm and an EMI SE value of 41 dB upon optimizing the MXene content. Additionally, the MBCA film demonstrated a consistent, rapid-response photothermal conversion capability, achieving a photothermal conversion temperature of 97 °C under a light intensity of 200 mW/m2. Consequently, this tough and multifunctional EMI shielding film holds substantial promise for protecting electronic equipment.

High-value utilization of pineapple leaf fibers towards high-performance electromagnetic shielding materials

As wearable electronics and wireless communications grow in popularity, high-performance electromagnetic interference (EMI) shielding materials are being explored for reducing serious radiation pollution. In this work, the high aspect ratio and high crystallinity of pineapple leaf nanofibers (PALNF), extracted and separated from the agricultural waste of pineapple leaves, are being considered potential dispersants and binders for assisting in the fabrication of ultrathin, highly flexible and mechanically robust Ti3C2Tx MXene/PALNF EMI shielding films. The “bricks-and-mortars” composite film containing only 50 wt % PALNF exhibits a superior tensile strength (up to 159.6 MPa), fracture strain (up to 6.7%), and toughness (up to 5.8 MJ/m3), which is several times or dozens of times higher than other reported freestanding MXene film. In particular, the composite film with a ratio of 1: 1 displays outstanding specific EMI shielding properties of 6541.1 dB cm2 g−1 in the X-band at a thickness of only 28 μm. Thus, from the perspective of “waste to wealth” and nacre bionics, recycling waste pineapple leaves through reprocessing into high-value EMI shielding films is a feasible way to reduce environmental problems caused by these wastes and electromagnetic radiation.

Integrated super-engineering polymeric electromagnetic interference shielding films withstanding the extreme environments

The electromagnetic interference (EMI) poses a threat to electronic equipment and human health, which has spawned the development of polymer-based EMI shielding materials. However, it is challenging to combine their ease of fabrication with extreme environmental resistance. Herein, a simple and consecutive bottom-up assembly route is developed to prepare EMI shielding films based on a super-engineering polymer named polyarylene ether nitrile (PEN). Thanks to the morphological transformation of PEN films, the integration of polymeric matrix and commercial carbon nanotubes is throughout the vacuum-assisted deposition and hot-press molding, resulting in a series of sandwiched nanocomposite films. In the whole X-band, the EMI SE of the nanocomposite film is up to 30 dB with a low thickness of 0.268 mm. Besides, the absorption coefficient (A) can be significantly increased to 0.93, exhibiting an excellent adsorption-dominant shielding mechanism. Due to the super-engineering polymer as a matrix, the sandwiched nanocomposite films are endowed with excellent thermal stability (Td5 = 512 °C), superior tensile strength (69 MPa) as well as improved hydrophobicity (103°). Notably, the EMI shielding and mechanical performances manifest outstanding reliability under harsh environments, including strong acid, alkali, and high-temperature treatments. The integrated preparation towards super-engineered polymer-based nanocomposites is efficient and economical, affording EMI shielding films resisting multiple harsh environments.

Bacterial-Cellulose-Reinforced Graphite Nanoplate Films for Electromagnetic Interference Shielding, Heat Conduction, and Joule Heating

With the flourishing development of wireless communication, there is an urgent need for flexible and robust materials with excellent thermal conductivity (TC) and electromagnetic interference (EMI) shielding performance through simple and green preparation. In this work, we efficiently prepared bacterial-cellulose-reinforced graphite nanoplate (BC-GNP) composite films by the vacuum filtration of BC/GNP mixture dispersions. Compared with the pure GNP film with a loose and disordered structure, the BC-GNP composite showed a highly aligned and compact “brick-and-mortar” structure. Benefiting from the unique structure, the resultant BC-GNP with 20 wt % BC (20%BC) exhibited a high tensile strength of 47.3 ± 1.8 MPa and an electrical conductivity of 76.9 ± 3.3 S/cm. As expected, the 20%BC showed excellent EMI shielding effectiveness (EMI SE) of 36.4 dB and a specific EMI SE (SSE/t) value of 8860 ± 400 dB·cm2/g with a thickness of 38 ± 1 μm. The in-plane TC and anisotropy index could reach up to 80.2 ± 6.4 W/mK and 73 ± 3, respectively. The 20%BC also exhibited a satisfactory Joule heating performance of 139 °C at a voltage of 6 V. More importantly, the 20%BC possessed a biodegradable property, which would completely degrade after 5 days. Thus, this work provides a strategy to facilely prepare biodegradable, high-performance, and multifunctional materials for wearable devices.

Free-standing polymer/multiwalled carbon nanotubes composite thin films for high thermal conductivity and prominent EMI shielding

Lightweight composite materials with efficient thermal conductivity (TC) and high electromagnetic interference (EMI) shielding effectiveness (SE) are of paramount importance for a wide range of applications such as electronics, aerospace, and stealth technology. In this work, lightweight, flexible, and free-standing poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/multiwalled carbon nanotube (MWCNT) composite thin films are fabricated by a single-step, solution casting method. Fabricated PVDF-HFP/MWCNT composite thin films are characterized by many physicochemical techniques such as Raman spectra, Fourier transform infrared spectra, X-ray diffractometer, and high-resolution transmission electron microscope. The resulting composite thin film exhibits a TC of 1.1 Wm−1K−1 at room temperature. Further analysis shows that the TC of the composite film is increased up to 1.8 Wm−1K−1 at 100 °C. As fabricated flexible and free-standing composite thin film (thickness ∼ 150 µm) exhibit an excellent EMI SE of ∼ 36 dB in the X-band region (8.2–12.4 GHz) at just 15 wt. % loading of MWCNT. The outstanding EMI shielding and high TC of PVDF-HFP/MWCNT composite films are attributed to the homogenous distribution and well-connected network of MWCNT within the polymer matrix, forming a conductive network throughout the composite film.

MXene/bacterial cellulose/Fe3O4/methyltrimethoxylsilane flexible film with hydrophobic for effective electromagnetic shielding

Electromagnetic (EM) pollution has become a serious problem in modern society as it affects human lives. The fabrication of strong and highly flexible materials for electromagnetic interference (EMI) shielding applications is extremely urgent. Herein, a MXene Ti3C2Tx/Fe3O4 & bacterial cellulose (BC)/Fe3O4&Methyltrimethoxysilane (MTMS) flexible hydrophobic electromagnetic shielding film (SBTFX-Y, X and Y were the number of layers of BC/Fe3O4 and the layers of Ti3C2Tx/Fe3O4), was fabricated. In the prepared film, MXene Ti3C2Tx absorbs a large amount of radio waves through polarization relaxation and conduction loss. Because of its extremely low reflectance of electromagnetic waves, BC@Fe3O4, as the outermost layer of the material, allows more electromagnetic waves to incident inside the material. The maximum electromagnetic interference (EMI) shielding efficiency (SE) of 68 dB was achieved for the composite film at 45 μm thickness. What's more, the SBTFX-Y films show excellent mechanical properties, hydrophobicity and flexibility. The unique stratified structure of the film provides a new strategy for designing high-performance EMI shielding films with excellent surface and mechanical properties.

Flexible and ultrathin GO@MXene sandwich-type multilayered film toward superior electromagnetic interference shielding in a wide gigahertz range of 3.95–18.0 GHz

Conductive MXene-based films are potential in electromagnetic interference (EMI) shielding. However, multilayered MXene-based films are rarely reported, and the EMI shielding investigations are confined in only X band (8–12 GHz). Herein, sandwich-type multilayered [email protected] films were constructed by an alternating vacuum-assisted filtration technique. Benefiting from interlayer scattering and high conductivity, the flexible multilayered [email protected] films show excellent EMI shielding performance in 3.95–18.0 GHz at an ultrathin film thickness. The mechanical properties and EMI shielding performance are related to the layered structure, film thickness and content of MXene. Especially, the trilaminar [email protected] film (only ∼8 µm) shows superior EMI shielding and mechanical properties. The average EMI shielding effectiveness (SE) values are 44.5, 46.6 and 45.0 dB at C, X and Ku bands, respectively, with the corresponding specific EMI SE values of 22,429.4, 23,487.9 and 22,681.5 dB cm2 g−1. The [email protected] film exhibits remarkable stability in acid, alkaline and organic solvent. This work not only provides a flexible film with high EMI shielding performance at a wide gigahertz range, but also suggests that the mechanical properties and EMI shielding can be tuned by simply changing the layered structure. This is helpful to give guidance to the design of novel MXene-based EMI shielding films and expand their applications.

Responsive polymer thin films

Responsive polymer thin films

Nanostructured Films of Ordered Fe Nanowires for High-Performance Transparent Electromagnetic Interference Shielding

Although metal nanowires (NWs), such as silver NWs, are ideal materials for flexible transparent electromagnetic shielding films, the challenge of obtaining absorptive shielding films with high transmittance and shielding efficiency (SE) still exists. To address this issue, this study used iron nanowires (Fe NWs) with excellent microwave absorbing properties to construct structures with ordered NW distributions. A series of polyethylene terephthalate (PET)/Fe NWs/poly (3,4-ethylenedioxythiophene) (PEDOT) electromagnetic interference (EMI) shielding films were prepared using the magnetic-field-induced orientation. The results demonstrate that the ordered Fe NW network structure can effectively overcome the problem of the trade-off between light transmittance and EMI SE. Specifically, at a Fe NW surface density of 201.78 mg/m2, the ordered PET/Fe NWs/PEDOT films demonstrated a 49.06% increase in light transmittance and a 32.94% increase in EMI SE (19.37 dB), compared to the films with randomly distributed Fe NWs. Furthermore, constructing a double-layer Fe NW network with a stagger angle of 45° at the same surface density increased the EMI SE by 73.2% relative to the monolayer-ordered Fe NW structure, reaching an SE value of 33.54 dB, while maintaining almost unchanged light transmittance. Additionally, the PET/Fe NWs/PEDOT films maintain 97.4% of EMI performance after 3000 bending cycles. Overall, this study provides a new approach for creating high-performance flexible transparent EMI shielding films.

Scalable Fabrication of Nacre-Structured Graphene/Polytetrafluoroethylene Films for Outstanding EMI Shielding Under Extreme Environment.

In this work, inspired by the great advantage of the unique "brick-mortar" layered structure as electromagnetic interference (EMI) shielding materials, a multifunctional flexible graphene nanosheets (GNS)/polytetrafluoroethylene (PTFE) composite film with excellent EMI shielding effects, impressive Joule heating performance, and light-to-heat conversion efficiency is fabricated based on the self-emulsifying process of PTFE. Both PTFE microspheres and nanofibers are employed together for the first time as "sand and cement" to build unique nacre-structured EMI shielding materials. Such configuration can obviously enhance the adhesion of composites and improve their mechanical property for the application under extreme environment. Moreover, the simple and effective repetitive roll pressing method can be used for the scalable production in industrialization. The GNS/PTFE composite film shows a high EMI shielding effectiveness (SE) of 50.85dB. Furthermore, it has a high thermal conductivity of 16.54W (m K)-1 , good flexibility, and recyclable properties. The excellent fire-resistant and hydrophobic properties of GNS/PTFE film also ensure its reliability and safety in practical application. In conclusion, the GNS/PTFE film demonstrates the potential for industrial manufacturing, and outstanding EMI shielding performance with high stability and durability, which has a broad application prospect for electronic devices in practical extreme outdoor environments.

Transparent and Stretchable Electromagnetic Interference Shielding Film with Fence-like Aligned Silver Nanowire Conductive Network.

Flexible transparent conductive electrodes (TCEs) that can be used as electromagnetic interference (EMI) shielding materials have a great potential for use as electronic components in optical window and display applications. However, development of TCEs that display high shielding effectiveness (SE) and good stretchability for flexible electronic device applications has proven challenging. Herein, this study describes a stretchable polydimethylsiloxane (PDMS)/silver nanowire (AgNW) TCE with a fence-like aligned conductive network that is fabricated via pre-stretching method. The fence-like AgNW network endowed the PDMS/AgNW film with excellent optoelectronic properties, i.e., low sheet resistance of 7.68Ωsq-1 at 73.7% optical transmittance, thus causing an effective EMI SE of 32.2dB at X-band. More importantly, the fence-like aligned AgNW conductive network reveals a high stability toward tensile deformation, thus gives the PDMS/AgNW film stretch-stable conductivity and EMI shielding property in the strain range of 0-100%. Typically, the film can reserve ≈70% or 80% of its initial EMI SE when stretching at 100% strain or stretching/releasing (50% strain) for 128 cycles, respectively. Additionally, the film exhibits a low-voltage driven and stretchable Joule heating performance. With these overall performances, the PDMS/AgNW film should be well suited for use in flexible and stretchable optical electronic devices.

Graphene/carbon nanotube/polypyrrole composite films for electromagnetic interference shielding

AbstractPolypyrrole (PPy), an ideal organic electroactive material, shows limited application in the field of electromagnetic interference (EMI) shielding for its relatively low shielding effectiveness (SE), significant stiffness, difficult solubility, and poor processing performance. A strategy is proposed to construct three‐dimensional network structures of graphene/CNT/polypyrrole by electrochemical deposition to improve the EMI SE of polypyrrole composite films. In the graphene/CNT/polypyrrole films, the graphene/CNT substrates form the skeletons, and polypyrrole acts as bridges between graphene sheets and CNTs to form percolation networks in the multiphase and multihierarchical nanocomposites. When the deposition time increases to 80 min, the content of polypyrrole increases to 30 wt%, the conductivity improves by 27.7%, and the EMI SE improves by 11.4% at X‐band. The final film thickness is 249 μm, the conductivity is 3.06 S/mm, and the average EMI SE is 59.6 dB.

Engineering the electronic structure on MXenes via multidimensional component interlayer insertion for enhanced electromagnetic shielding

• CNTs/Ni hybrids were used as an isolation agent to disperse Ti 3 C 2 T x sheets in the interlayers, which form a multiple-dimensional laminated structure. • Introduction of 2D hexagonal magnetic Ni flakes boosts interfacial polarization and magnetic-responding ability, visualized by electron holography. • The 3D freestanding films can achieve precise regulation of components and excellent EMI shielding performance (67.4 dB). MXene-based functional electromagnetic interference (EMI) shielding films are highly desirable for modern integrated electronic and telecommunication systems in aerospace, military, artificial intelligence, and smart and wearable electronics field. In this work, 3D freestanding Ti 3 C 2 T x /CNTs/Ni film assembled by 1D multi-walled carbon nanotubes (MWCNTs)/Ni and 2D Ti 3 C 2 T x MXene sheets was synthesized by a facile vacuum filtration process. By electrostatic incorporation, hexagonal nickel plates embed on the CNTs and then the CNTs/Ni insert into the Ti 3 C 2 T x layers to form magnetized Ti 3 C 2 T x -based functional film with a compact and laminated structure. Due to the outstanding electron migration capacity in the highly conductive Ti 3 C 2 T x sheet and multiple internal reflections from porous and segregated structures, the optimized Ti 3 C 2 T x /CNTs/Ni composite films show excellent EMI shielding effectiveness of 67.4 dB with electrical conductivity of 744 S cm –1 . Surprisingly, a magnetization compensation strategy is built to boost the EMI shielding effectiveness with decreased conductivity. Meanwhile, the visual magnetic coupling phenomenon and charge distribution in the heterogeneous interfaces could be observed in the reconstructed electron holography images. Those encouraging results shed light on novel magnetized MXene-based functional films for high-performance EMI shielding.

Transparent and high-performance electromagnetic interference shielding composite film based on single-crystal graphene/hexagonal boron nitride heterostructure

The multiple requirements of optical transmittance, high shielding effectiveness, and long-term stability bring considerable challenge to electromagnetic interference (EMI) shielding in the fields of visualization windows, transparent optoelectronic devices, and aerospace equipment. To this end, attempts were hereby made, and based on high-quality single crystal graphene (SCG)/hexagonal boron nitride (h-BN) heterostructure, transparent EMI shielding films with weak secondary reflection, nanoscale ultra-thin thickness and long-term stability were finally realized by a composite structure. In this novel structure, SCG was adopted as the absorption layer, while sliver nanowires (Ag NWs) film acted as the reflection layer. These two layers were placed on different sides of the quartz to form a cavity, which achieved the dual coupling effect, so that the electromagnetic wave was reflected multiple times to form more absorption loss. Among the absorption dominant shielding films, the composite structure in this work demonstrated stronger shielding effectiveness of 28.76 dB with a higher light transmittance of 80.6%. In addition, under the protection of the outermost h-BN layer, the decline range of the shielding performance of the shielding film was extensively reduced after 30 days of exposure to air and maintained long-term stability. Overall, this study provides an outstanding EMI shielding material with great potential for practical applications in electronic devices protection.