Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fif...Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fifth-generation communication equipment.In this study,multistage microcellular waterborne polyurethane(WPU)composites were constructed via gradient induction,layer-by-layer casting,and supercritical carbon dioxide foaming.The gradient-structured WPU/ironcobalt loaded reduced graphene oxide(FeCo@rGO)foam serves as an impedance-matched absorption layer,while the highly conductive WPU/silver loaded glass microspheres(Ag@GM)layer is employed as a reflection layer.Thanks to the incorporation of an asymmetric structure,as well as the introduction of gradient and porous configurations,the composite foam demonstrates excellent conductivity,outstanding EMI SE(74.9 dB),and minimal reflection characteristics(35.28%)in 8.2-12.4 GHz,implying that more than 99.99999%of electromagnetic(EM)waves were blocked and only 35.28%were reflected to the external environment.Interestingly,the reflectivity of the composite foam is reduced to 0.41%at 10.88 GHz due to the resonance for incident and reflected EM waves.Beyond that,the composite foam is characterized by low density(0.47 g/cm^(3))and great stability of EMI shielding properties.This work offers a viable approach for craft-ing lightweight,highly shielding,and minimally reflective EMI shielding composites.展开更多
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication,...Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.展开更多
Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.Howev...Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.However,its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation.Here,an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression.Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton(denoted as AMLM-PM foam).Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films.Therefore,the resistance change of AMLM-PM reaches four orders of magnitude under compression.Moreover,the inter-skeleton conductive films can improve the mechanical strength of foam,prevent the leakage of liquid metal and increase the scattering area of EM wave.AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness,solving the problem of traditional CPFs upon compression.The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function.展开更多
Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,...Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,a hierarchical polyimide(PI)nonwoven fabric is fabricated by alkali treatment,in-situ growth of magnetic particles and"self-activated"electroless Ag plating process.Especially,the hierarchical impedance matching can be constructed by systematically assembling Fe_(3)O_(4)/Ag-loaded PI nonwoven fabric(PFA)and pure Ag-coated PI nonwoven fabric(PA),endowing it with an ultralowreflectivity EMI shielding performance.In addition,thermal insulation of fluffy three-dimensional(3D)space structure in PFA and low infrared emissivity of PA originated from Ag plating bring an excellent infrared stealth performance.More importantly,the strong bonding interaction between Fe_(3)O_(4),Ag,and PI fiber improves thermal stability in EMI shielding and high-temperature resistant infrared stealth performance.Such excellent comprehensive performance makes it promising for military tents to protect internal equipment from electromagnetic interference stemmed from adjacent equipment and/or enemy,and inhibit external infrared detection.展开更多
The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of ...The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of polymer particles and the formation of interactions with conductive fillers remain signifi-cant challenges for polydimethylsiloxane,which are crucial to the construction of a segregated structure.In this work,MXene sheets were functionalized and assembled onto the surface of polydimethylsilox-ane microspheres via hydrophobic interaction.Subsequently,functionalized MXene/polydimethylsiloxane(FMP)composites with a segregated structure were fabricated by filtration and hot-pressing.The FMP composite containing 8.22 wt.%MXene exhibited a high electrical conductivity of 99.4 S m^(−1)and a sat-isfactory EMI shielding effectiveness/thickness(EMI SE/d)of 31.3 dB mm^(−1).Furthermore,the FMP com-posite demonstrated excellent reliability with over 90%retention of EMI shielding effectiveness under harsh environments such as ultra-high/low temperatures and acidic/alkaline solutions.Additionally,the photothermal conversion performance of FMP composites and the capacitive sensing performance of the sensor based on FMP composites indicated their potential for managing body temperature and moni-toring human movement.Consequently,FMP composites show great promise in wearable electronics for effective electromagnetic interference shielding,thermal management and capacitive sensing.展开更多
The impact of Y content on the microstructure,mechanical properties,and electromagnetic interference shielding effectiveness(EMI SE)of the Mg-6Zn-xY-1La-0.5Zr alloy was investigated.After the extrusion treatment of Mg...The impact of Y content on the microstructure,mechanical properties,and electromagnetic interference shielding effectiveness(EMI SE)of the Mg-6Zn-xY-1La-0.5Zr alloy was investigated.After the extrusion treatment of Mg-6Zn-xY-1La-0.5Zr alloy,the large grains that did not experience dynamic recrystallization were elongated along the extrusion direction,and the small-sized dynamic recrystallized grains were distributed around the large grains.The Mg-6Zn-1Y-1La-0.5Zr alloy demonstrated a favorable balance between strength and plasticity,exhibiting ultimate tensile strength,yield strength,and elongation values of 332.3 MPa,267.3 MPa,and 16.2%,respectively.Moreover,the EMI SE within the frequency range of 30-1500 MHz changes from 79 to 110 dB,aligning with the electromagnetic shielding requirements of many high-strength applications.展开更多
Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high...Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high conductivity and effective absorption-dominated electromagnetic interference(EMI)shielding,as dictated by classical impedance matching theory.This study addresses these limitations by introducing a novel synthesis of aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels.Leveraging the unique properties of polyelectrolytes,this innovative approach enhances ionic conductivity and exploits the hydration effect of hydrophilic polar groups to induce the formation of intermediate water.This critical innovation facilitates polarization relaxation and rearrangement in response to electromagnetic fields,thereby significantly enhancing the EMI shielding effectiveness of hydrogels.The electromagnetic wave attenuation capacity of these hydrogels was thoroughly evaluated across both X-band and terahertz band frequencies,with further investigation into the impact of varying water content states-hydrated,dried,and frozen-on their electromagnetic properties.Moreover,the hydrogels exhibited promising capabilities beyond mere EMI shielding;they also served effectively as strain sensors for monitoring human motions,indicating their potential applicability in wearable electronics.This work provides a new approach to designing multifunctional hydrogels,advancing the integration of flexible,multifunctional materials in modern electronics,with potential applications in both EMI shielding and wearable technology.展开更多
Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution an...Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.展开更多
With the rapid development of electronic detective techniques,there is an urgent need for broadband(from microwave to infrared)stealth of aerospace equipment.However,achieving effective broadband stealth primarily rel...With the rapid development of electronic detective techniques,there is an urgent need for broadband(from microwave to infrared)stealth of aerospace equipment.However,achieving effective broadband stealth primarily relies on the composite of multi-layer coatings of different materials,while realizing broadband stealth with a single material remains a significant challenge.Herein,we reported a highly compact MXene film with aligned nanosheets through a continuous centrifugal spraying strategy.The film exhibits an exceptional electromagnetic interference shielding effectiveness of 45 d B in gigahertz band(8.2-40 GHz)and 59 d B in terahertz band(0.2-1.6 THz)at a thickness of 2.25μm,owing to the high conductivity(1.03×10^(6)S m^(-1)).Moreover,exceptionally high specific shielding effectiveness of 1.545×10^(6)dB cm^(2)g^(-1)has been demonstrated by the film,which is the highest value reported for shielding films.Additionally,the film exhibits an ultra-low infrared emissivity of 0.1 in the wide-range infrared band(2.5-16.0μm),indicating its excellent infrared stealth performance for day-/nighttime outdoor environments.Moreover,the film demonstrates efficient electrothermal performance,including a high saturated temperature(over 120℃ at 1.0 V),a high heating rate(4.4℃s^(-1)at 1.0 V),and a stable and uniform heating distribution.Therefore,this work provides a promising strategy for protecting equipment from multispectral electromagnetic interference and inhibiting infrared detection.展开更多
Stretchable conductive fibers are essential for the advancement of wearable electronic textiles.However,a significant challenge arises as their conductivity sharply decreases when stretched due to disruptions in elect...Stretchable conductive fibers are essential for the advancement of wearable electronic textiles.However,a significant challenge arises as their conductivity sharply decreases when stretched due to disruptions in electronic transport.Coating fibers with soft liquid metal(LM)has emerged as a promising solution.Despite this,there remains an urgent need to develop methods that enhance LM adhesion to substrates while facilitating efficient electron transport pathways.This study demonstrates a novel Ag-LM conductive network strategy for fabricating a thermoplastic polyurethane/polydopamine/silver-LM(TPU/PDA/Ag-LM)fiber membrane.This membrane exhibits outstanding stretchable electromagnetic interference(EMI)shielding performance and is produced through straightforward electrospinning,electroless depositing,and LM coating and activation.The TPU/PDA/Ag fiber membrane is initially prepared via polydopamineassisted deposition of silver nanoparticles(AgNPs)on electrospun TPU fibers.The presence of AgNPs on the surface of TPU/PDA fibers enhances LM adhesion to the substrate and bridges adjacent LM to establish efficient conductive paths.This interaction benefits from the reactive alloying between AgNPs and LM,where the LM infiltrates the gaps among AgNPs,forming a distinctive LM-Ag alloy layer that uniformly coats the surface of TPU fibers.As anticipated,the unique three-dimensional(3D)interconnected LM-Ag conductive network remains intact during stretching,ensuring strain-invariant conductivity.The fabricated TPU/PDA/Ag-LM fiber membrane demonstrates exceptional EMI shielding effectiveness(SE)of 77.4 dB within the frequency range of 8.2-12.8 GHz and maintains an excellent EMI SE of 37.2 dB under extensive tensile deformation of 300%.Furthermore,the TPU/PDA/Ag-LM fiber membrane shows remarkable mechanical properties and stable Joule heating performance even under significant stretching.展开更多
With the rapid development of 5G communication technology and wearable electronic devices,the demand for low-reflection electromagnetic interference(EMI)shielding materials is becoming increasingly urgent.In this work...With the rapid development of 5G communication technology and wearable electronic devices,the demand for low-reflection electromagnetic interference(EMI)shielding materials is becoming increasingly urgent.In this work,reduced graphene oxide-MXene(rGMH)@FeNi/epoxy EMI shielding composites with a regular honeycomb structure were successfully prepared by the combination of surface functionalization modification,sacrificial template,and freeze-drying.The effects of magnetic FeNi alloy particle loading mode and loading amount on the EMI shielding performance of composites were investigated.The results show that rGMH@FeNi/epoxy EMI shielding composites have the highest EMI shielding effectiveness(EMI SE)and the lowest reflection shielding effectiveness when magnetic FeNi alloy particles are loaded only on the graphene skeleton.In this composite,the EMI SE value of the composite is 61 dB when the rGMH@FeNi mass fraction is 5.4 wt%(f-FeNi mass fraction is 0.9 wt%),which is 4.7 times that of the blended rGO/MXene/FeNi/epoxy resin composite(13 dB)with the same mass fraction.At the same time,the rGMH@FeNi/epoxy composite has excellent thermal stability(heat-resistance index of 190.3℃)and mechanical properties(energy storage modulus of 8606.7 MPa).These polymer-based EMI shielding composites with excellent EMI shielding properties and low reflection effectiveness have great potential in the protection of high-power,portable and wearable electronic devices against electromagnetic pollution.展开更多
The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflect...The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.展开更多
Lightweight,ultra-flexible,and robust crosslinked transition metal carbide(Ti3C2 MXene)coated polyimide(PI)(C-MXene@PI)porous composites are manufactured via a scalable dip-coating followed by chemical crosslinking ap...Lightweight,ultra-flexible,and robust crosslinked transition metal carbide(Ti3C2 MXene)coated polyimide(PI)(C-MXene@PI)porous composites are manufactured via a scalable dip-coating followed by chemical crosslinking approach.In addition to the hydrophobicity,anti-oxidation and extreme-temperature stability,efficient utilization of the intrinsic conductivity of MXene,the interfacial polarization between MXene and PI,and the micrometer-sized pores of the composite foams are achieved.Consequently,the composites show a satisfactory X-band electromagnetic interference(EMI)shielding effectiveness of 22.5 to 62.5 dB at a density of 28.7 to 48.7 mg cm−3,leading to an excellent surface-specific SE of 21,317 dB cm^(2)g^(−1).Moreover,the composite foams exhibit excellent electrothermal performance as flexible heaters in terms of a prominent,rapid reproducible,and stable electrothermal effect at low voltages and superior heat performance and more uniform heat distribution compared with the commercial heaters composed of alloy plates.Furthermore,the composite foams are well attached on a human body to check their electromechanical sensing performance,demonstrating the sensitive and reliable detection of human motions as wearable sensors.The excellent EMI shielding performance and multifunctionalities,along with the facile and easy-to-scalable manufacturing techniques,imply promising perspectives of the porous C-MXene@PI composites in next-generation flexible electronics,aerospace,and smart devices.展开更多
The rapid development of aerospace weapons and equipment,wireless base stations and 5G communication technologies has put forward newer and higher requirements for the comprehensive performances of polymer-based elect...The rapid development of aerospace weapons and equipment,wireless base stations and 5G communication technologies has put forward newer and higher requirements for the comprehensive performances of polymer-based electromagnetic interference(EMI)shielding composites.However,most of currently prepared polymer-based EMI shielding composites are still difficult to combine high performance and multi-functionality.In response to this,based on the research works of relevant researchers as well as our research group,three possible directions to break through the above bottlenecks are proposed,including construction of efficient conductive networks,optimization of multi-interfaces for lightweight and multifunction compatibility design.The future development trends in three directions are prospected,and it is hoped to provide certain theoretical basis and technical guidance for the preparation,research and development of polymer-based EMI shielding composites.展开更多
Although electrically conductive and hydrophilic MXene sheets are promising for multifunctional fibers and electronic textiles,it is still a challenge to simultaneously enhance both conductivity and mechanical propert...Although electrically conductive and hydrophilic MXene sheets are promising for multifunctional fibers and electronic textiles,it is still a challenge to simultaneously enhance both conductivity and mechanical properties of MXene fibers because of the high rigidity of MXene sheets and insufficient inter-sheet interactions.Herein,we demonstrate a core-shell wet-spinning methodology for fabricating highly conductive,super-tough,ultra-strong,and environmentally stable Ti_(3)C_(2)T_(x) MXene-based core-shell fibers with conductive MXene cores and tough aramid nanofiber(ANF)shells.The highly orientated and low-defect structure endows the ANF@MXene core-shell fiber with supertoughness of~48.1 MJ m^(-3),high strength of~502.9 MPa,and high conductivity of~3.0×10^(5)S m^(-1).The super-tough and conductive ANF@MXene fibers can be woven into textiles,exhibiting an excellent electromagnetic interference(EMI)shielding efficiency of 83.4 dB at a small thickness of 213μm.Importantly,the protection of the ANF shells provides the fibers with satisfactory cyclic stability under dynamic stretching and bending,and excellent resistance to acid,alkali,seawater,cryogenic and high temperatures,and fire.The oxidation resistance of the fibers is demonstrated by their wellmaintained EMI shielding performances.The multifunctional core-shell fibers would be highly promising in the fields of EMI shielding textiles,wearable electronics and aerospace.展开更多
Conductive hydrogels have potential applications in shielding electromagnetic(EM)radiation interference in deformable and wearable electronic devices,but usually suffer from poor environmental stability and stretching...Conductive hydrogels have potential applications in shielding electromagnetic(EM)radiation interference in deformable and wearable electronic devices,but usually suffer from poor environmental stability and stretching-induced shielding performance degradation.Although organohydrogels can improve the environmental stability of materials,their development is at the expense of reducing electrical conductivity and thus weakening EM interference shielding ability.Here,a MXene organohydrogel is prepared which is composed of MXene network for electron conduction,binary solvent channels for ion conduction,and abundant solvent-polymer-MXene interfaces for EM wave scattering.This organohydrogel possesses excellent anti-drying ability,low-temperature tolerance,stretchability,shape adaptability,adhesion and rapid self-healing ability.Two effective strategies have been proposed to solve the problems of current organohydrogel shielding materials.By reasonably controlling the MXene content and the glycerol-water ratio in the gel,MXene organohydrogel can exhibit exceptionally enhanced EM interference shielding performances compared to MXene hydrogel due to the increased physical cross-linking density of the gel.Moreover,MXene organohydrogel shows attractive stretching-enhanced interference effectiveness,caused by the connection and parallel arrangement of MXene nanosheets.This well-designed MXene organohydrogel has potential applications in shielding EM interference in deformable and wearable electronic devices.展开更多
With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted world...With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention.Therefore,the design and development of highly efficient EMI shielding materials are of great importance.In this work,the three-dimensional graphene oxide(GO)with regular honeycomb structure(GH)is firstly constructed by sacrificial template and freeze-dry-ing methods.Then,the amino functionalized FeNi alloy particles(f-FeNi)are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.Finally,the rGH@FeNi/epoxy EMI shielding com-posites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin.Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect,the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt%(rGH and f-FeNi are 1.2 and 0.9 wt%,respectively)exhibit a high EMI shielding effectiveness(EMI SE)of 46 dB,which is 5.8 times of that(8 dB)for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction.At the same time,the rGH@FeNi/epoxy composites also possess excellent thermal stability(heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0°C respectively)and mechanical properties(storage modulus is 8296.2 MPa).展开更多
With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materia...With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materials have disadvantages such as high density,easy corrosion,difficult processing and high price,etc.Polymer matrix EMI shielding composites possess light weight,corrosion resistance and easy processing.However,the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance.This review firstly discusses the key concept,loss mechanism and test method of EMI shielding.Then the current development status of EMI shielding materials is summarized,and the research progress of polymer matrix EMI shielding composites with different structures is illustrated,especially for their preparation methods and evaluation.Finally,the corresponding key scientific and technical problems are proposed,and their development trend is also prospected.展开更多
Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/ca...Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/carbon nanotube/polyimide(gradient-conductive MXene/CNT/PI,GCMCP)aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection.The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly(amic acid)inks with different CNT contents,where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer.In addition,the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections.Consequently,the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency(68.2 dB)and low reflection(R=0.23).Furthermore,the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission,which shows a prosperous application prospect in defense industry and aerospace.展开更多
基金supported by the Natural Science Foundation of Anhui Province(No.2308085QE146 and 2208085ME116)the National Natural Science Foundation of China(No.52173039)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210894)the Anhui Provincial Universities Outstanding Youth Research Project(No.2023AH020018).
文摘Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fifth-generation communication equipment.In this study,multistage microcellular waterborne polyurethane(WPU)composites were constructed via gradient induction,layer-by-layer casting,and supercritical carbon dioxide foaming.The gradient-structured WPU/ironcobalt loaded reduced graphene oxide(FeCo@rGO)foam serves as an impedance-matched absorption layer,while the highly conductive WPU/silver loaded glass microspheres(Ag@GM)layer is employed as a reflection layer.Thanks to the incorporation of an asymmetric structure,as well as the introduction of gradient and porous configurations,the composite foam demonstrates excellent conductivity,outstanding EMI SE(74.9 dB),and minimal reflection characteristics(35.28%)in 8.2-12.4 GHz,implying that more than 99.99999%of electromagnetic(EM)waves were blocked and only 35.28%were reflected to the external environment.Interestingly,the reflectivity of the composite foam is reduced to 0.41%at 10.88 GHz due to the resonance for incident and reflected EM waves.Beyond that,the composite foam is characterized by low density(0.47 g/cm^(3))and great stability of EMI shielding properties.This work offers a viable approach for craft-ing lightweight,highly shielding,and minimally reflective EMI shielding composites.
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
基金supported by the Fundamental Research Funds for the Central Universities and Heilongjiang Provincial Natural Science Foundation of China(Grant No.YQ2020E009).
文摘Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.
基金supported by National Key Research and Development Program of China(2021YBF3501304)National Natural Science Foundation of China(52222106,52371171,51971008,52121001)Natural Science Foundation of Beijing Municipality(2212033).
文摘Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.However,its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation.Here,an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression.Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton(denoted as AMLM-PM foam).Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films.Therefore,the resistance change of AMLM-PM reaches four orders of magnitude under compression.Moreover,the inter-skeleton conductive films can improve the mechanical strength of foam,prevent the leakage of liquid metal and increase the scattering area of EM wave.AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness,solving the problem of traditional CPFs upon compression.The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function.
基金support from the National Natural Science Foundation of China(52373077,52003106,52103074,52233006,52161135302)the Research Foundation Flanders(G0F2322N)Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-03-E00108).
文摘Designing and fabricating a compatible low-reflectivity electromagnetic interference(EMI)shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military.Hence,a hierarchical polyimide(PI)nonwoven fabric is fabricated by alkali treatment,in-situ growth of magnetic particles and"self-activated"electroless Ag plating process.Especially,the hierarchical impedance matching can be constructed by systematically assembling Fe_(3)O_(4)/Ag-loaded PI nonwoven fabric(PFA)and pure Ag-coated PI nonwoven fabric(PA),endowing it with an ultralowreflectivity EMI shielding performance.In addition,thermal insulation of fluffy three-dimensional(3D)space structure in PFA and low infrared emissivity of PA originated from Ag plating bring an excellent infrared stealth performance.More importantly,the strong bonding interaction between Fe_(3)O_(4),Ag,and PI fiber improves thermal stability in EMI shielding and high-temperature resistant infrared stealth performance.Such excellent comprehensive performance makes it promising for military tents to protect internal equipment from electromagnetic interference stemmed from adjacent equipment and/or enemy,and inhibit external infrared detection.
基金supported by the Fundamental Research Funds for the Central Universities(No.D5000220252)the funds for Ministry of Industry and Information Technology(No.MJZ44N22)Shaanxi Undergraduate Training Program for Innovation and Entrepreneurship(No.S202310699509).
文摘The formation of segregated structure has been demonstrated as an effective strategy for achieving ex-ceptional electromagnetic interference(EMI)shielding performance at low filler loadings.However,the acquisition of polymer particles and the formation of interactions with conductive fillers remain signifi-cant challenges for polydimethylsiloxane,which are crucial to the construction of a segregated structure.In this work,MXene sheets were functionalized and assembled onto the surface of polydimethylsilox-ane microspheres via hydrophobic interaction.Subsequently,functionalized MXene/polydimethylsiloxane(FMP)composites with a segregated structure were fabricated by filtration and hot-pressing.The FMP composite containing 8.22 wt.%MXene exhibited a high electrical conductivity of 99.4 S m^(−1)and a sat-isfactory EMI shielding effectiveness/thickness(EMI SE/d)of 31.3 dB mm^(−1).Furthermore,the FMP com-posite demonstrated excellent reliability with over 90%retention of EMI shielding effectiveness under harsh environments such as ultra-high/low temperatures and acidic/alkaline solutions.Additionally,the photothermal conversion performance of FMP composites and the capacitive sensing performance of the sensor based on FMP composites indicated their potential for managing body temperature and moni-toring human movement.Consequently,FMP composites show great promise in wearable electronics for effective electromagnetic interference shielding,thermal management and capacitive sensing.
基金supported from the National Key R&D Program of China(No.2021YFB3701100)the National Natural Science Foundation of China(No.52225101)+1 种基金the Fundamental Research Funds for the Central Universities of China(Nos.2023CDJYXTD-002,2020CDJDPT001)the Graduate Research and Innovation Foundation of Chongqing,China(No.CYB23037).
文摘The impact of Y content on the microstructure,mechanical properties,and electromagnetic interference shielding effectiveness(EMI SE)of the Mg-6Zn-xY-1La-0.5Zr alloy was investigated.After the extrusion treatment of Mg-6Zn-xY-1La-0.5Zr alloy,the large grains that did not experience dynamic recrystallization were elongated along the extrusion direction,and the small-sized dynamic recrystallized grains were distributed around the large grains.The Mg-6Zn-1Y-1La-0.5Zr alloy demonstrated a favorable balance between strength and plasticity,exhibiting ultimate tensile strength,yield strength,and elongation values of 332.3 MPa,267.3 MPa,and 16.2%,respectively.Moreover,the EMI SE within the frequency range of 30-1500 MHz changes from 79 to 110 dB,aligning with the electromagnetic shielding requirements of many high-strength applications.
基金supported by the National Natural Science Foundation of China(52375204)Shaanxi Provincial Science and Technology Innovation Team(2024RS-CXTD-63)+4 种基金Xianyang 2023 Key Research and Development Plan(L2023-ZDYF-QYCX-009)the Fundamental Research Funds for the Central Universities(D5000230356)2024“Double First-Class University”Construction Special Fund Project(0604024GH0201332,0604024SH0201332)Zhiyuan Laboratory(NO.ZYL2024007)Horizon Europe Framework Programme(101086071-CUPOLA).
文摘Conductive hydrogels have garnered widespread attention as a versatile class of flexible electronics.Despite considerable advancements,current methodologies struggle to reconcile the fundamental trade-off between high conductivity and effective absorption-dominated electromagnetic interference(EMI)shielding,as dictated by classical impedance matching theory.This study addresses these limitations by introducing a novel synthesis of aramid nanofiber/MXene-reinforced polyelectrolyte hydrogels.Leveraging the unique properties of polyelectrolytes,this innovative approach enhances ionic conductivity and exploits the hydration effect of hydrophilic polar groups to induce the formation of intermediate water.This critical innovation facilitates polarization relaxation and rearrangement in response to electromagnetic fields,thereby significantly enhancing the EMI shielding effectiveness of hydrogels.The electromagnetic wave attenuation capacity of these hydrogels was thoroughly evaluated across both X-band and terahertz band frequencies,with further investigation into the impact of varying water content states-hydrated,dried,and frozen-on their electromagnetic properties.Moreover,the hydrogels exhibited promising capabilities beyond mere EMI shielding;they also served effectively as strain sensors for monitoring human motions,indicating their potential applicability in wearable electronics.This work provides a new approach to designing multifunctional hydrogels,advancing the integration of flexible,multifunctional materials in modern electronics,with potential applications in both EMI shielding and wearable technology.
基金the National Natural Science Foundation of China(52090034,52273064,52221006)the Fundamental Research Funds for the Central Universities(JD2417)is gratefully acknowledged.
文摘Although multifunctional electromagnetic interference(EMI)shielding materials with ultrahigh electromagnetic wave absorption are highly required to solve increasingly serious electromagnetic radiation and pollution and meet multi-scenario applications,EMI shielding materials usually cause a lot of reflection and have a single function.To realize the broadband absorption-dominated EMI shielding via absorption-reflection-reabsorption mechanisms and the interference cancelation effect,multifunctional asymmetric bilayer aerogels are designed by sequential printing of a MXene-graphene oxide(MG)layer with a MG emulsion ink and a conductive MXene layer with a MXene ink and subsequent freeze-drying for generating and solidifying numerous pores in the aerogels.The top MG layer of the asymmetric bilayer aerogel optimizes impedance matching and achieves re-absorption,while the bottom MXene layer enhances the reflection of the incident electromagnetic waves.As a result,the asymmetric bilayer aerogel achieves an average absorption coefficient of 0.95 in the X-band and shows the tunable absorption ability to electromagnetic wave in the ultrawide band from 8.2 to 40 GHz.Finite element simulations substantiate the effectiveness of the asymmetric bilayer aerogel for electromagnetic wave absorption.The multifunctional bilayer aerogels exhibit hydrophobicity,thermal insulation and Joule heating capacities and are efficient in solar-thermal/electric heating,infrared stealth,and clean-up of spilled oil.
基金financially supported by the National Natural Science Foundation of China(Grant no.52371247 and 52072415)。
文摘With the rapid development of electronic detective techniques,there is an urgent need for broadband(from microwave to infrared)stealth of aerospace equipment.However,achieving effective broadband stealth primarily relies on the composite of multi-layer coatings of different materials,while realizing broadband stealth with a single material remains a significant challenge.Herein,we reported a highly compact MXene film with aligned nanosheets through a continuous centrifugal spraying strategy.The film exhibits an exceptional electromagnetic interference shielding effectiveness of 45 d B in gigahertz band(8.2-40 GHz)and 59 d B in terahertz band(0.2-1.6 THz)at a thickness of 2.25μm,owing to the high conductivity(1.03×10^(6)S m^(-1)).Moreover,exceptionally high specific shielding effectiveness of 1.545×10^(6)dB cm^(2)g^(-1)has been demonstrated by the film,which is the highest value reported for shielding films.Additionally,the film exhibits an ultra-low infrared emissivity of 0.1 in the wide-range infrared band(2.5-16.0μm),indicating its excellent infrared stealth performance for day-/nighttime outdoor environments.Moreover,the film demonstrates efficient electrothermal performance,including a high saturated temperature(over 120℃ at 1.0 V),a high heating rate(4.4℃s^(-1)at 1.0 V),and a stable and uniform heating distribution.Therefore,this work provides a promising strategy for protecting equipment from multispectral electromagnetic interference and inhibiting infrared detection.
基金supported by the National Natural Sci-ence Foundation of China(No.12072325)the Natural Science Foundation of Henan Province(No.20A430028).
文摘Stretchable conductive fibers are essential for the advancement of wearable electronic textiles.However,a significant challenge arises as their conductivity sharply decreases when stretched due to disruptions in electronic transport.Coating fibers with soft liquid metal(LM)has emerged as a promising solution.Despite this,there remains an urgent need to develop methods that enhance LM adhesion to substrates while facilitating efficient electron transport pathways.This study demonstrates a novel Ag-LM conductive network strategy for fabricating a thermoplastic polyurethane/polydopamine/silver-LM(TPU/PDA/Ag-LM)fiber membrane.This membrane exhibits outstanding stretchable electromagnetic interference(EMI)shielding performance and is produced through straightforward electrospinning,electroless depositing,and LM coating and activation.The TPU/PDA/Ag fiber membrane is initially prepared via polydopamineassisted deposition of silver nanoparticles(AgNPs)on electrospun TPU fibers.The presence of AgNPs on the surface of TPU/PDA fibers enhances LM adhesion to the substrate and bridges adjacent LM to establish efficient conductive paths.This interaction benefits from the reactive alloying between AgNPs and LM,where the LM infiltrates the gaps among AgNPs,forming a distinctive LM-Ag alloy layer that uniformly coats the surface of TPU fibers.As anticipated,the unique three-dimensional(3D)interconnected LM-Ag conductive network remains intact during stretching,ensuring strain-invariant conductivity.The fabricated TPU/PDA/Ag-LM fiber membrane demonstrates exceptional EMI shielding effectiveness(SE)of 77.4 dB within the frequency range of 8.2-12.8 GHz and maintains an excellent EMI SE of 37.2 dB under extensive tensile deformation of 300%.Furthermore,the TPU/PDA/Ag-LM fiber membrane shows remarkable mechanical properties and stable Joule heating performance even under significant stretching.
基金support and funding from the National Natural Science Foundation of China(Nos.52303104,52203100 and 52403132)Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20240455)+4 种基金Basic Research Program of Natural Science of Shaanxi Province(No.2024JCYBMS-275)Natural Science Foundation of Chongqing,China(No.2023NSCQ-MSX2682)the Doctoral Research Start-up Funds of Xi’an University of Technology(No.108/451122007)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2024094)the Transformation Projects of Scientific and Technological Achievements of Qinchuangyuan Platform(2023JH-QCYCK-0026).
文摘With the rapid development of 5G communication technology and wearable electronic devices,the demand for low-reflection electromagnetic interference(EMI)shielding materials is becoming increasingly urgent.In this work,reduced graphene oxide-MXene(rGMH)@FeNi/epoxy EMI shielding composites with a regular honeycomb structure were successfully prepared by the combination of surface functionalization modification,sacrificial template,and freeze-drying.The effects of magnetic FeNi alloy particle loading mode and loading amount on the EMI shielding performance of composites were investigated.The results show that rGMH@FeNi/epoxy EMI shielding composites have the highest EMI shielding effectiveness(EMI SE)and the lowest reflection shielding effectiveness when magnetic FeNi alloy particles are loaded only on the graphene skeleton.In this composite,the EMI SE value of the composite is 61 dB when the rGMH@FeNi mass fraction is 5.4 wt%(f-FeNi mass fraction is 0.9 wt%),which is 4.7 times that of the blended rGO/MXene/FeNi/epoxy resin composite(13 dB)with the same mass fraction.At the same time,the rGMH@FeNi/epoxy composite has excellent thermal stability(heat-resistance index of 190.3℃)and mechanical properties(energy storage modulus of 8606.7 MPa).These polymer-based EMI shielding composites with excellent EMI shielding properties and low reflection effectiveness have great potential in the protection of high-power,portable and wearable electronic devices against electromagnetic pollution.
基金supported by National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2024-00335216,RS-2024-00407084 and RS-2023-00207836)Korea Environment Industry&Technology Institute(KEITI)through the R&D Project of Recycling Development for Future Waste Resources Program,funded by the Korea Ministry of Environment(MOE)(2022003500003).
文摘The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.
基金support of the Qilu Young Scholar Program of Shandong University(No.31370082163127)the authors acknowledge funding from the support from the Chinese Scholarship Council(to NW,project#201709370040).
文摘Lightweight,ultra-flexible,and robust crosslinked transition metal carbide(Ti3C2 MXene)coated polyimide(PI)(C-MXene@PI)porous composites are manufactured via a scalable dip-coating followed by chemical crosslinking approach.In addition to the hydrophobicity,anti-oxidation and extreme-temperature stability,efficient utilization of the intrinsic conductivity of MXene,the interfacial polarization between MXene and PI,and the micrometer-sized pores of the composite foams are achieved.Consequently,the composites show a satisfactory X-band electromagnetic interference(EMI)shielding effectiveness of 22.5 to 62.5 dB at a density of 28.7 to 48.7 mg cm−3,leading to an excellent surface-specific SE of 21,317 dB cm^(2)g^(−1).Moreover,the composite foams exhibit excellent electrothermal performance as flexible heaters in terms of a prominent,rapid reproducible,and stable electrothermal effect at low voltages and superior heat performance and more uniform heat distribution compared with the commercial heaters composed of alloy plates.Furthermore,the composite foams are well attached on a human body to check their electromechanical sensing performance,demonstrating the sensitive and reliable detection of human motions as wearable sensors.The excellent EMI shielding performance and multifunctionalities,along with the facile and easy-to-scalable manufacturing techniques,imply promising perspectives of the porous C-MXene@PI composites in next-generation flexible electronics,aerospace,and smart devices.
基金The authors are grateful for the supports from the National Natural Science Foundation of China(U21A2093)Y.L.Zhang would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2021107)+1 种基金This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin ScholarsOpen access funding provided by Shanghai Jiao Tong University
文摘The rapid development of aerospace weapons and equipment,wireless base stations and 5G communication technologies has put forward newer and higher requirements for the comprehensive performances of polymer-based electromagnetic interference(EMI)shielding composites.However,most of currently prepared polymer-based EMI shielding composites are still difficult to combine high performance and multi-functionality.In response to this,based on the research works of relevant researchers as well as our research group,three possible directions to break through the above bottlenecks are proposed,including construction of efficient conductive networks,optimization of multi-interfaces for lightweight and multifunction compatibility design.The future development trends in three directions are prospected,and it is hoped to provide certain theoretical basis and technical guidance for the preparation,research and development of polymer-based EMI shielding composites.
基金Financial support from the National Natural Science Foundation of China(51922020,52090034)the Fundamental Research Funds for the Central Universities(BHYC1707B,XK1802-2)。
文摘Although electrically conductive and hydrophilic MXene sheets are promising for multifunctional fibers and electronic textiles,it is still a challenge to simultaneously enhance both conductivity and mechanical properties of MXene fibers because of the high rigidity of MXene sheets and insufficient inter-sheet interactions.Herein,we demonstrate a core-shell wet-spinning methodology for fabricating highly conductive,super-tough,ultra-strong,and environmentally stable Ti_(3)C_(2)T_(x) MXene-based core-shell fibers with conductive MXene cores and tough aramid nanofiber(ANF)shells.The highly orientated and low-defect structure endows the ANF@MXene core-shell fiber with supertoughness of~48.1 MJ m^(-3),high strength of~502.9 MPa,and high conductivity of~3.0×10^(5)S m^(-1).The super-tough and conductive ANF@MXene fibers can be woven into textiles,exhibiting an excellent electromagnetic interference(EMI)shielding efficiency of 83.4 dB at a small thickness of 213μm.Importantly,the protection of the ANF shells provides the fibers with satisfactory cyclic stability under dynamic stretching and bending,and excellent resistance to acid,alkali,seawater,cryogenic and high temperatures,and fire.The oxidation resistance of the fibers is demonstrated by their wellmaintained EMI shielding performances.The multifunctional core-shell fibers would be highly promising in the fields of EMI shielding textiles,wearable electronics and aerospace.
基金This work was financially supported by Beijing Natural Science Foundation(2212033)National Natural Science Foundation of China(51971008,U1832138,51731002 and 51671010)+1 种基金the Fundamental Research Funds for the Central UniversitiesOpen access funding provided by Shanghai Jiao Tong University
文摘Conductive hydrogels have potential applications in shielding electromagnetic(EM)radiation interference in deformable and wearable electronic devices,but usually suffer from poor environmental stability and stretching-induced shielding performance degradation.Although organohydrogels can improve the environmental stability of materials,their development is at the expense of reducing electrical conductivity and thus weakening EM interference shielding ability.Here,a MXene organohydrogel is prepared which is composed of MXene network for electron conduction,binary solvent channels for ion conduction,and abundant solvent-polymer-MXene interfaces for EM wave scattering.This organohydrogel possesses excellent anti-drying ability,low-temperature tolerance,stretchability,shape adaptability,adhesion and rapid self-healing ability.Two effective strategies have been proposed to solve the problems of current organohydrogel shielding materials.By reasonably controlling the MXene content and the glycerol-water ratio in the gel,MXene organohydrogel can exhibit exceptionally enhanced EM interference shielding performances compared to MXene hydrogel due to the increased physical cross-linking density of the gel.Moreover,MXene organohydrogel shows attractive stretching-enhanced interference effectiveness,caused by the connection and parallel arrangement of MXene nanosheets.This well-designed MXene organohydrogel has potential applications in shielding EM interference in deformable and wearable electronic devices.
基金supports from the National Natural Science Foundation of China(U21A2093 and 51903145)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)and Fundamental Research Funds for the Central Universities(D5000210627)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention.Therefore,the design and development of highly efficient EMI shielding materials are of great importance.In this work,the three-dimensional graphene oxide(GO)with regular honeycomb structure(GH)is firstly constructed by sacrificial template and freeze-dry-ing methods.Then,the amino functionalized FeNi alloy particles(f-FeNi)are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.Finally,the rGH@FeNi/epoxy EMI shielding com-posites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin.Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect,the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt%(rGH and f-FeNi are 1.2 and 0.9 wt%,respectively)exhibit a high EMI shielding effectiveness(EMI SE)of 46 dB,which is 5.8 times of that(8 dB)for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction.At the same time,the rGH@FeNi/epoxy composites also possess excellent thermal stability(heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0°C respectively)and mechanical properties(storage modulus is 8296.2 MPa).
基金funding from the Foundation of National Natural Science Foundation of China(51903145 and 51973173)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+1 种基金Fundamental Research Funds for the Central Universities(D5000210627)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materials have disadvantages such as high density,easy corrosion,difficult processing and high price,etc.Polymer matrix EMI shielding composites possess light weight,corrosion resistance and easy processing.However,the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance.This review firstly discusses the key concept,loss mechanism and test method of EMI shielding.Then the current development status of EMI shielding materials is summarized,and the research progress of polymer matrix EMI shielding composites with different structures is illustrated,especially for their preparation methods and evaluation.Finally,the corresponding key scientific and technical problems are proposed,and their development trend is also prospected.
基金the National Natural Science Foundation of China(52073053,52233006)Young Elite Scientists Sponsorship Program by CAST(2021QNRC001)+3 种基金Shanghai Rising-Star Program(21QA1400300)Innovation Program of Shanghai Municipal Education Commission(2021-01-0700-03-E00108)Science and Technology Commission of Shanghai Municipality(20520741100)China Postdoctoral Science Foundation(2021M690596)。
文摘Construction of advanced electromagnetic interference(EMI)shielding materials with miniaturized,programmable structure and low reflection are promising but challenging.Herein,an integrated transition-metal carbides/carbon nanotube/polyimide(gradient-conductive MXene/CNT/PI,GCMCP)aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection.The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly(amic acid)inks with different CNT contents,where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer.In addition,the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections.Consequently,the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency(68.2 dB)and low reflection(R=0.23).Furthermore,the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission,which shows a prosperous application prospect in defense industry and aerospace.
