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
Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films play a pivotal role in 5 G communication technology,smart wearables,automotive electronics,and aerospace.In this work,(...Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films play a pivotal role in 5 G communication technology,smart wearables,automotive electronics,and aerospace.In this work,(Ti_(3)C_(2)T_(x) MXene/cellulose nanofibers(CNF)-(hydroxy‑functionalized BNNS(BNNS-OH)/CNF)composite films(TBCF)with Janus structure are prepared via vacuum-assisted filtration of BNNS-OH/CNF and Ti_(3)C_(2)T_(x)/CNF suspension by one after another.Then ionic bonding-strengthened TBCF(ITBCF)is obtained by Ca^(2+)ion infiltration and cold-pressing technique.The Janus structure endows ITBCF with the unique“conductive on one side and insulating on the other”property.When the mass ratio of Ti_(3)C_(2)T_(x) and BNNS is 1:1 and the total mass fraction is 70 wt.%,the electrical conductivity(σ)of the Ti_(3)C_(2)T_(x)/CNF side of ITBCF reaches 166.7 S/cm,while the surface resistivity of the BNNS-OH/CNF side is as high as 304 MΩ.After Ca^(2+)ion infiltration,the mechanical properties of ITBCF are significantly enhanced.The tensile strength and modulus of ITBCF are 73.5 MPa and 15.6 GPa,which are increased by 75.9%and 46.2%compared with those of TBCF,respectively.Moreover,ITBCF exhibits outstanding EMI shielding effectiveness(SE)of 57 dB and thermal conductivity(λ)of 9.49 W/(m K).In addition,ITBCF also presents excellent photothermal and photoelectric energy conversion performance.Under simulated solar irradiation with a power density of 120 mW/cm^(2),the surface stabilization temperature reaches up to 65.3°C and the maximum steady state voltage reaches up to 58.2 mV.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
With the continuous advancement of electronic devices,flexible thin films with both thermal manage-ment functions and excellent electromagnetic interference(EMI)shielding properties have received much attention.Hence,...With the continuous advancement of electronic devices,flexible thin films with both thermal manage-ment functions and excellent electromagnetic interference(EMI)shielding properties have received much attention.Hence,inspired by Janus,a CNF/MXene/ZnFe2O4@PANI composite film with an asymmetric gradient alternating structure was successfully prepared by adjusting the filler content of the conduc-tive and magnetic layers using a vacuum-assisted filtration method.Benefiting from the magnetic reso-nance and hysteresis loss of ZnFe2O4@PANI,conductive loss and dipole polarization of MXene,as well as the exclusive"absorption-reflection-reabsorption"shielding feature in the alternating multilayered films,CM&CZFP-4 G film has superior EMI shielding performance,with an EMI SE of up to 45.75 dB and shield-ing effectiveness of 99.99%.Surprisingly,the composite film maintains reliable EMI shielding properties even after prolonged erosion in harsh environments such as high/low temperatures,high humidity,acids and alkalis.Furthermore,the CM&CZFP-4 G responded quickly within about 50 s and reached a maximum steady-state temperature of 235.8℃ at an applied voltage of 9.0 V,indicating the obtained film acquired outstanding and controllable Joule heating performance.This result was attributed to the homogeneous dispersion of MXene to build up a conductive network and endow the CNF/MXene with high conduc-tivity.Meanwhile,the fire resistance of CM&CZFP-4 G was significantly improved compared to pure CNF,which guaranteed fire safety during its application.Additionally,contributed by long fiber entanglement of CNF,extensive hydrogen-bonding interactions and multilayer structural design,the CM&CZFP-4 G film exhibits excellent mechanical characteristics,with the tensile strength and fracture strain of 27.74 MPa and 6.21%,separately.This work offers a creative avenue to prepare multifunctional composite films with electromagnetic shielding and Joule heating for various application environments.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
Electromagnetic interference shielding materials are inevitably damaged during service,causing a serious decline in their shielding performance.Therefore,it is urgent to develop polymer-based composites with excellent...Electromagnetic interference shielding materials are inevitably damaged during service,causing a serious decline in their shielding performance.Therefore,it is urgent to develop polymer-based composites with excellent electromagnetic shielding and self-healing properties.In this study,a layered foam/film structure polycaprolactone composite characterized by electric/magnetic bifunctionality was constructed by a hot-pressing process and supercritical carbon dioxide foaming.The microcellular framework offers rich heterogeneous interfaces and improves electromagnetic attenuation capabilities.Such a reasonable construction of asymmetric shielding networks optimizes the impedance matching,while the incident electromagnetic waves form a special attenuation mode of“absorption-reflection-reabsorption”.The polycaprolactone composite foam exhibits an excellent electromagnetic interference shielding effectiveness of 53.6 dB in the X-band and a low reflection value of only 0.36,effectively reducing secondary pollution.In addition,the damaged polycaprolactone composite foam exhibits over 93%electromagnetic interference shielding effectiveness and healing efficiency,ensuring the long-term stability of the material in practical applications.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
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
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 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
Two-dimensional transition metal carbon/nitrides(MXenes)have emerged as prominent materials in the development of high-performance electromagnetic interference(EMI)shielding films owing to their ex-ceptional electrica...Two-dimensional transition metal carbon/nitrides(MXenes)have emerged as prominent materials in the development of high-performance electromagnetic interference(EMI)shielding films owing to their ex-ceptional electrical conductivity,special layered structure,and chemically active surfaces.Substantial ef-forts have been devoted to addressing the poor mechanical strength and limited functionality of pure MXene films through structural design and interfacial reinforcement.However,there is a notable lack of a systematic review of the research on MXene-based EMI shielding films with multi-layer structures,which could provide a theoretical foundation and technical guidance for the development and application of shielding films.This review aims to summarize the recent advancements in MXene-based layered films for EMI shielding.First,the structure and properties of MXene nanosheets are systematically introduced.Next,the optimization of layered structures and interfacial reinforcement strategies in MXene-based EMI shielding films are objectively reviewed,followed by a discussion of their multifunctional compatibility.Finally,future prospects and challenges for MXene-based layered EMI shielding films are highlighted.展开更多
Power grid is an indispensable infrastructure in modern society,in order to ensure the normal operation of the grid,online non-contact monitoring of high-voltage lines is essential.In this work,a‘capacitor-laser diod...Power grid is an indispensable infrastructure in modern society,in order to ensure the normal operation of the grid,online non-contact monitoring of high-voltage lines is essential.In this work,a‘capacitor-laser diode(LD)-capacitor’structure,namely,laser diode in capacitors(LDIC),that can be used for non-contact monitoring of high-voltage(HV)line status by directly transferring the status information of the HV line to modulated laser pulses is proposed.The proposed LDIC can accurately extract the real-time voltage changes on the HV line with an accuracy level of 0.959%.Because the LDIC is sensitive to high-frequency electromagnetic field,the LDIC is successfully utilised to detect the external electromagnetic interference(EMI)to obtain the intensity and frequency of the external EMI.Additionally,the amplitude and frequency of the HV line vibration can be accurately monitored by using the LDIC.For the third-order curve fitting of vibration amplitude,the average error is only 0.00867,and the average error of linear fitting of vibration frequency is as low as 0.00655.This work provides a novel approach for the online monitoring of the HV line status and a new supplement for the development of power grid technology.展开更多
With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response...With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response. Accordingly, appropriate EMI shielding materials are crucial to blocking harmful electromagnetic radiation and passing serviceable electromagnetic waves. Smart EMI shielding materials that can dynamically adjust their EMI shielding effectiveness (SE) in response to specific application requirements and environmental changes are extremely advantageous in both military and civil areas. To date, materials with adjustable EMI SE for various responses have been developed. This review pays special attention to smart materials with tunable EMI SE. The design strategies, mechanism and recent progress of smart EMI shielding materials are discussed together with different stimuli responses, including compression strain, tensile strain, chemical reagent, shape memory, phase transition and crossover angle change-induced responses. The review ends up to discuss challenges and perspectives for smart EMI shielding materials.展开更多
The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In th...The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.展开更多
Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electroni...Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electronics,posing a major obstacle to the integra-tion of electronics.The innovation of integrating 3D-printed conformal shielding(c-SE)modules with packaging materials onto core electronics offers infinite possibilities to satisfy ideal SE func-tion without occupying additional space.Herein,the 3D printable carbon-based inks with various proportions of graphene and carbon nanotube nanoparticles are well-formulated by manipulating their rheological peculiarity.Accordingly,the free-constructed architectures with arbitrarily-customized structure and multifunctionality are created via 3D printing.In particular,the SE performance of 3D-printed frame is up to 61.4 dB,simultaneously accompanied with an ultralight architecture of 0.076 g cm^(-3) and a superhigh specific shielding of 802.4 dB cm3 g^(-1).Moreover,as a proof-of-concept,the 3D-printed c-SE module is in situ integrated into core electronics,successfully replacing the traditional metal-based module to afford multiple functions for electromagnetic compatibility and thermal dissipa-tion.Thus,this scientific innovation completely makes up the blank for assembling carbon-based c-SE modules and sheds a brilliant light on developing the next generation of high-performance shielding materials with arbitrarily-customized structure for integrated electronics.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financially supported by the National Natural Science Foundation of China(Nos.52303090,52403132,52403112,52473083)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-QN-0168,2024JC-TBZC-04)+6 种基金the Innovation Capability Support Plan of Shaanxi Province(No.2024ZC-KJXX-022)the Shaanxi Province Key Research and Development Plan Project(No.2023-YBGY-461)the Innovation Capability Support Program of Shaanxi(No.2024RS-CXTD-57)the Natural Science Foundation of Chongqing,China(No.2023NSCQ-MSX2547)the Youth Talent Promotion Project of Shaanxi Science and Technology Association(No.20240426)The Special Scientific Research Plan of Education Department of Shaanxi Province(No.23JK0376)the authors would also like to thank Shiyaniia lab for the sup-port of SEM and XPS tests.
文摘Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films play a pivotal role in 5 G communication technology,smart wearables,automotive electronics,and aerospace.In this work,(Ti_(3)C_(2)T_(x) MXene/cellulose nanofibers(CNF)-(hydroxy‑functionalized BNNS(BNNS-OH)/CNF)composite films(TBCF)with Janus structure are prepared via vacuum-assisted filtration of BNNS-OH/CNF and Ti_(3)C_(2)T_(x)/CNF suspension by one after another.Then ionic bonding-strengthened TBCF(ITBCF)is obtained by Ca^(2+)ion infiltration and cold-pressing technique.The Janus structure endows ITBCF with the unique“conductive on one side and insulating on the other”property.When the mass ratio of Ti_(3)C_(2)T_(x) and BNNS is 1:1 and the total mass fraction is 70 wt.%,the electrical conductivity(σ)of the Ti_(3)C_(2)T_(x)/CNF side of ITBCF reaches 166.7 S/cm,while the surface resistivity of the BNNS-OH/CNF side is as high as 304 MΩ.After Ca^(2+)ion infiltration,the mechanical properties of ITBCF are significantly enhanced.The tensile strength and modulus of ITBCF are 73.5 MPa and 15.6 GPa,which are increased by 75.9%and 46.2%compared with those of TBCF,respectively.Moreover,ITBCF exhibits outstanding EMI shielding effectiveness(SE)of 57 dB and thermal conductivity(λ)of 9.49 W/(m K).In addition,ITBCF also presents excellent photothermal and photoelectric energy conversion performance.Under simulated solar irradiation with a power density of 120 mW/cm^(2),the surface stabilization temperature reaches up to 65.3°C and the maximum steady state voltage reaches up to 58.2 mV.
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supported by the National Natural Science Foundation of China(Nos.22005277,52474256 and 52074247)the Natural Science Foundation of Hubei Province(No.2024AFB662)+1 种基金the Young Top-notch Talent Cultivation Program of Hubei Province,Opening Foundation of State Key Laboratory of Organic-Inorganic Composites,Beijing University of Chemical Technology(No.oic-202401012)the Fundamental Research Funds for National Universities,China University of Geosciences(No.2024XLA93).
文摘With the continuous advancement of electronic devices,flexible thin films with both thermal manage-ment functions and excellent electromagnetic interference(EMI)shielding properties have received much attention.Hence,inspired by Janus,a CNF/MXene/ZnFe2O4@PANI composite film with an asymmetric gradient alternating structure was successfully prepared by adjusting the filler content of the conduc-tive and magnetic layers using a vacuum-assisted filtration method.Benefiting from the magnetic reso-nance and hysteresis loss of ZnFe2O4@PANI,conductive loss and dipole polarization of MXene,as well as the exclusive"absorption-reflection-reabsorption"shielding feature in the alternating multilayered films,CM&CZFP-4 G film has superior EMI shielding performance,with an EMI SE of up to 45.75 dB and shield-ing effectiveness of 99.99%.Surprisingly,the composite film maintains reliable EMI shielding properties even after prolonged erosion in harsh environments such as high/low temperatures,high humidity,acids and alkalis.Furthermore,the CM&CZFP-4 G responded quickly within about 50 s and reached a maximum steady-state temperature of 235.8℃ at an applied voltage of 9.0 V,indicating the obtained film acquired outstanding and controllable Joule heating performance.This result was attributed to the homogeneous dispersion of MXene to build up a conductive network and endow the CNF/MXene with high conduc-tivity.Meanwhile,the fire resistance of CM&CZFP-4 G was significantly improved compared to pure CNF,which guaranteed fire safety during its application.Additionally,contributed by long fiber entanglement of CNF,extensive hydrogen-bonding interactions and multilayer structural design,the CM&CZFP-4 G film exhibits excellent mechanical characteristics,with the tensile strength and fracture strain of 27.74 MPa and 6.21%,separately.This work offers a creative avenue to prepare multifunctional composite films with electromagnetic shielding and Joule heating for various application environments.
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Financial support from the National Research Foundation of Korea grant funded by the Korean government(No.2022R1F1A1074210)the University Natural Science Research Projects of Anhui Province(No.2024AH050145)is gratefully acknowledged.
文摘Electromagnetic interference shielding materials are inevitably damaged during service,causing a serious decline in their shielding performance.Therefore,it is urgent to develop polymer-based composites with excellent electromagnetic shielding and self-healing properties.In this study,a layered foam/film structure polycaprolactone composite characterized by electric/magnetic bifunctionality was constructed by a hot-pressing process and supercritical carbon dioxide foaming.The microcellular framework offers rich heterogeneous interfaces and improves electromagnetic attenuation capabilities.Such a reasonable construction of asymmetric shielding networks optimizes the impedance matching,while the incident electromagnetic waves form a special attenuation mode of“absorption-reflection-reabsorption”.The polycaprolactone composite foam exhibits an excellent electromagnetic interference shielding effectiveness of 53.6 dB in the X-band and a low reflection value of only 0.36,effectively reducing secondary pollution.In addition,the damaged polycaprolactone composite foam exhibits over 93%electromagnetic interference shielding effectiveness and healing efficiency,ensuring the long-term stability of the material in practical applications.
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 the Key Research and Development Project of Henan Province of China(No.241111232300)the National Natural Science Foundation of China(Nos.52303113 and 5227308)the Open Project Program of Yaoshan Laboratory(No.2024003).
文摘Two-dimensional transition metal carbon/nitrides(MXenes)have emerged as prominent materials in the development of high-performance electromagnetic interference(EMI)shielding films owing to their ex-ceptional electrical conductivity,special layered structure,and chemically active surfaces.Substantial ef-forts have been devoted to addressing the poor mechanical strength and limited functionality of pure MXene films through structural design and interfacial reinforcement.However,there is a notable lack of a systematic review of the research on MXene-based EMI shielding films with multi-layer structures,which could provide a theoretical foundation and technical guidance for the development and application of shielding films.This review aims to summarize the recent advancements in MXene-based layered films for EMI shielding.First,the structure and properties of MXene nanosheets are systematically introduced.Next,the optimization of layered structures and interfacial reinforcement strategies in MXene-based EMI shielding films are objectively reviewed,followed by a discussion of their multifunctional compatibility.Finally,future prospects and challenges for MXene-based layered EMI shielding films are highlighted.
基金supported by National Key R&D Program of China under Grant No.2021YFB3600400Mindu Innovation Laboratory Project under Grant No.2020ZZ113.
文摘Power grid is an indispensable infrastructure in modern society,in order to ensure the normal operation of the grid,online non-contact monitoring of high-voltage lines is essential.In this work,a‘capacitor-laser diode(LD)-capacitor’structure,namely,laser diode in capacitors(LDIC),that can be used for non-contact monitoring of high-voltage(HV)line status by directly transferring the status information of the HV line to modulated laser pulses is proposed.The proposed LDIC can accurately extract the real-time voltage changes on the HV line with an accuracy level of 0.959%.Because the LDIC is sensitive to high-frequency electromagnetic field,the LDIC is successfully utilised to detect the external electromagnetic interference(EMI)to obtain the intensity and frequency of the external EMI.Additionally,the amplitude and frequency of the HV line vibration can be accurately monitored by using the LDIC.For the third-order curve fitting of vibration amplitude,the average error is only 0.00867,and the average error of linear fitting of vibration frequency is as low as 0.00655.This work provides a novel approach for the online monitoring of the HV line status and a new supplement for the development of power grid technology.
基金financially supported by the National Natural Science Foundation of China(No.52173264)the Natural Science Foundation Project of Chongqing(No.cstc2024ycjh-bgzxm0005).
文摘With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response. Accordingly, appropriate EMI shielding materials are crucial to blocking harmful electromagnetic radiation and passing serviceable electromagnetic waves. Smart EMI shielding materials that can dynamically adjust their EMI shielding effectiveness (SE) in response to specific application requirements and environmental changes are extremely advantageous in both military and civil areas. To date, materials with adjustable EMI SE for various responses have been developed. This review pays special attention to smart materials with tunable EMI SE. The design strategies, mechanism and recent progress of smart EMI shielding materials are discussed together with different stimuli responses, including compression strain, tensile strain, chemical reagent, shape memory, phase transition and crossover angle change-induced responses. The review ends up to discuss challenges and perspectives for smart EMI shielding materials.
基金This work was supported by the National Natural Science Foundation of China(No.U21A2093)the Anhui Provincial Natural Science Foundation(No.2308085QE146)the National Natural Science Foundation of Jiangsu Province(No.BK20210894).
文摘The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.
基金This work is financially supported by the National Natural Science Foundation of China(52303036)the Natural Science Foundation of Guangxi Province(2020GXNSFAA297028)+4 种基金the Guangxi Science and Technology Base and Talent Special Project(GUIKE AD23026179)the International Science&Technology Cooperation Project of Chengdu(2021-GH03-00009-HZ)the Program of Innovative Research Team for Young Scientists of Sichuan Province(22CXTD0019)the Natural Science Foundation of Sichuan Province(2023NSFSC0986)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Sklpme2023-3-18).
文摘Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electronics,posing a major obstacle to the integra-tion of electronics.The innovation of integrating 3D-printed conformal shielding(c-SE)modules with packaging materials onto core electronics offers infinite possibilities to satisfy ideal SE func-tion without occupying additional space.Herein,the 3D printable carbon-based inks with various proportions of graphene and carbon nanotube nanoparticles are well-formulated by manipulating their rheological peculiarity.Accordingly,the free-constructed architectures with arbitrarily-customized structure and multifunctionality are created via 3D printing.In particular,the SE performance of 3D-printed frame is up to 61.4 dB,simultaneously accompanied with an ultralight architecture of 0.076 g cm^(-3) and a superhigh specific shielding of 802.4 dB cm3 g^(-1).Moreover,as a proof-of-concept,the 3D-printed c-SE module is in situ integrated into core electronics,successfully replacing the traditional metal-based module to afford multiple functions for electromagnetic compatibility and thermal dissipa-tion.Thus,this scientific innovation completely makes up the blank for assembling carbon-based c-SE modules and sheds a brilliant light on developing the next generation of high-performance shielding materials with arbitrarily-customized structure for integrated electronics.
