The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D i...The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.展开更多
With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption ar...With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption are urgently required.This study presents a bio-inspired hierarchical composite foam fabricated using supercritical nitrogen foaming technology.This material exhibits a honeycomb structure,with pore cell sizes controllable within a range of 30–92μm by regulating the filler.The carbon fiber felt(CFf)provides efficient reflection of electromagnetic waves,while the chloroprene rubber/carbon fiber/carbon black foam facilitates both wave absorption and temperature monitoring through its optimized conductive network.This synergistic mechanism results in an EMI shielding effectiveness(SE)of 60.06 d B with excellent temperature sensing performance(The temperature coefficient of resistance(TCR)is-2.642%/℃)in the 24–70℃ range.Notably,the material has a thermal conductivity of up to 0.159 W/(m·K),and the bio-inspired layered design enables information encryption,demonstrating the material's potential for secure communication applications.The foam also has tensile properties of up to 5.13 MPa and a tear strength of 33.02 N/mm.This biomimetic design overcomes the traditional limitations of flexible materials and provides a transformative solution for next-generation applications such as flexible electronics,aerospace systems and military equipment,which urgently need integrated electromagnetic protection,thermal management and information security.展开更多
In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(...In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(CNT/cellulose-BN/PVA)composite.Using cellulose aerogel as a template,CNT were incorporated into the cellulose template by vertically impregnating the CNT suspension.Following the impregnation of BN/PVA and high-pressure compression,three-dimensional dual-continuous network structure was successfully constructed in the CNT/cellulose-BN/PVA composite.The comprehensive performance of the composite,including electromagnetic interference(EMI)shielding and Joule heating performance,was investigated.The results indicate that the total EMI shielding effectiveness(SE)for the CNT/cellulose-BN/PVA composite reveals similar values for electromagnetic waves incident from different directions,but totally different shielding mechanisms.For the CNT/cellulose-BN/PVA composite with three impregnation cycles of CNT,the EMI SE values exceeded 39 dB for electromagnetic waves incident from both the high-and low-CNT-content sides.93%of the microwaves were reflected when electromagnetic waves were incident from the high-CNT-content side,while the reflection coefficient decreased to 0.44 for the transverse direction.In addition,the construction of the dual-continuous network structure enabled the composite to exhibit both excellent electrical conductivity and good thermal conductivity simultaneously,endowing the material with good Joule heating performance.CNT/cellulose-BN/PVA composite films have significant potential for application as EMI shielding materials in extremely cold weather.展开更多
To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding ...To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding performances remains crucial challenges.Herein,we propose a hierarchical manufacturing method that combines the use of 3D printing shear flow field and layer-by-layer assembly for fabricating the structurally customizable and multifunctional polylactic acid@graphene nanoparticle(PLA@GNs)materials.The dynamic behavior of polymer fluids is firstly explored via computational fluid dynamic simulation,and a Weissenberg number is employed to quantitatively analyze the disordered-to-ordered structural evolution of molecular chains and nanoparticles,allowing to tailor the micro-scale ordered structures.Subsequently,the macro-scale 3D architectures of PLA@GNs modules are fabricated by layer-by-layer assembly.Owing to the aligned GNs,the shielding performance reaches 41.2 d B,simultaneously accompanied by a directional thermal conductivity of 3.2 W m^(-1)K^(-1).Moreover,the potential application of 3D-printed shielding modules in specific civilian frequency bands such as 4G(1800–2100 MHz),Bluetooth(2402–2480 MHz),and 5G(3300–3800 MHz)is fully demonstrated.Overall,this work not only establishes a universal methodology about 3D printing shear flow field-driven orientation of two-dimensional nanoparticles within polymer fluids,but also gives a scientific method for advanced manufacturing of the next-generation electromagnetic functional modules for smart electronics.展开更多
The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement...The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement of simultaneous high efficiency and low reflectivity across microwave,terahertz,and infrared spectra remains a formidable challenge.Herein,a carbonized MXene/polyimide(C-MXene/PI)aerogel material integrating a spatially coupled hierarchically anisotropic structure with stepwise conductivity gradients was constructed.Electromagnetic waves propagate through the top-down vertical disordered horizontal architecture and progressive conductivity gradient of C-MXene/PI aerogel,undergoing stepwise absorption-dissipation-re-dissipation processes.The C-MXene/PI aerogel exhibits an average electromagnetic interference(EMI)shielding effectiveness of91.0 dB in X-band and a reflection coefficient of 0.40.In the terahertz frequency band,the average EMI shielding performance reaches66.2 dB with a reflection coefficient of 0.33.Furthermore,the heterolayered porous architecture of C-MXene/PI aerogels exhibits low thermal conductivity and reduced infrared emissivity,enabling exceptional infrared stealth capability across the 2-16μm wavelength spectrum.This study provides an feasible strategy for constructing low-reflectivity multi-spectrum compatible shielding materials.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
Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and...Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.展开更多
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
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
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
Electromagnetic interference(EMI)shielding materials with adaptive strain capability have broad applications in wearable electronic devices.However,as an important candidate,compressible conductive foam generally suff...Electromagnetic interference(EMI)shielding materials with adaptive strain capability have broad applications in wearable electronic devices.However,as an important candidate,compressible conductive foam generally suffers from a reduction in EMI shielding performance during compression,which limits its application.Here,a compressible conductive aerogel with a unique conductive compensation effect is designed to solve this problem.CuS microspheres with metal-like conductivity serve as conductive compensation sites,and are chemically embedded in the skeletons of lamellar-structured carboxymethylcellulose(CMC)/MXene aerogel through Cu–S−Ti−C chemical bonds.The incorporation of CuS induces circularly-distributed interfacial polarization to enhance the attenuation of EM waves.More importantly,these CuS microspheres act as interlayer bridges to connect the upper and lower MXene/CMC layers during compression,thereby establishing numerous conductive compensation paths to offset the negative effect of thickness reduction on shielding performance.The optimized CMC/MXene/CuS aerogel shows stable EMI shielding performance during compression,and maintains a high shielding effectiveness of∼32.31 dB with increasing compressive strain.In addition,this composite aerogel exhibits good thermal insulation and sound absorption performances,achieving triple shielding functions against EM waves,heat and sound.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
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
The development of stretchable conductors with high deformation,conductivity,and thermal conductivity using liquid metal(LM)has sparked widespread interest in the fields of flexible electronics,electromagnetic interfe...The development of stretchable conductors with high deformation,conductivity,and thermal conductivity using liquid metal(LM)has sparked widespread interest in the fields of flexible electronics,electromagnetic interference(EMI),and multifunctional materi-als.However,fabricating desirable shielding materials by directly coating LMs on soft polymer substrates remains a challenge because of the huge surface tension and weak wettability of LMs.In this study,Ga-based composite paste is prepared from a mixture of Ga and dia-mond nonmetallic particles through ultrasonic fragmentation.At various temperatures,the resulting LM composite putty(LMP)exhibits soft and hard properties and can thus be molded into specific shapes according to application needs.In addition,the composite can be eas-ily coated onto polymer substrates,such as thermoplastic polyurethane(TPU)elastomer.The fabricated LMP–TPU exhibits an impress-ive shape deformation capacity of 1100%,demonstrating exceptional tensile properties and achieving electromagnetic interference–shielding effectiveness of up to 52 dB.Furthermore,it retains an ultrahigh conductivity of 20000 S/m,even under a strain of 600%.This feature further makes it a highly competitive multifunctional material.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
Over 950 billion(about 3.8 million tons)masks have been consumed in the last four years around the world to protect human beings from COVID-19 and air pollution.However,very few of these used masks are being recycled,...Over 950 billion(about 3.8 million tons)masks have been consumed in the last four years around the world to protect human beings from COVID-19 and air pollution.However,very few of these used masks are being recycled,with the majority of them being landfilled or incinerated.To address this issue,we propose a repurposing upcycling strategy by converting these polypropylene(PP)-based waste masks to highperformance thermally conductive nanocomposites(PP@G,where G refers to graphene)with exceptional electromagnetic interference shielding property.The PP@G is fabricated by loading tannic acid onto PP fibers via electrostatic self-assembling,followed by mixing with graphene nanoplatelets(GNPs).Because this strategy enables the GNPs to form efficient thermal and electrical conduction pathways along the PP fiber surface,the PP@G shows a high thermal conductivity of 87 W m^(-1)K^(-1)and exhibits an electromagnetic interference shielding effectiveness of 88 dB(1100 dB cm^(−1)),making it potentially applicable for heat dissipation and electromagnetic shielding in advanced electronic devices.Life cycle assessment and techno-economic assessment results show that our repurposing strategy has significant advantages over existing methods in reducing environmental impacts and economic benefits.This strategy offers a facile and promising approach to upcycling/repurposing of fibrous waste plastics.展开更多
Exploiting high-performance absorption-dominant electromagnetic interference(EMI)shielding composites is urgently desired yet challenging for minimizing secondary electromagnetic radiation pollution.Herein,a nickel(Ni...Exploiting high-performance absorption-dominant electromagnetic interference(EMI)shielding composites is urgently desired yet challenging for minimizing secondary electromagnetic radiation pollution.Herein,a nickel(Ni)shell was in-situ grown on a copper nanowires(CuNWs)core to greatly improve the stability of CuNWs,while maintaining excellent electrical conductivity.Afterward,Ni nanowires/Ni@Cu nanowires/graphite paper/waterborne polyurethane(NiNWs/Ni@CuNWs/graphite paper/WPU,n Ni-m Ni@Cu-G)composite foams with the multilayered gradient architectures were fabricated by a facile multi-step freeze-casting method.In the resultant composite foams,the lowly conductive porous NiNWs/WPU layer plays a role as the impedance matching layer,the moderately conductive porous Ni@CuNWs/WPU layer acts as the transition layer,and the highly conductive graphite paper layer serves as the reflection layer.Arising from the rational layout of multilayered gradient magnetic-electrical networks,n Ni-m Ni@Cu-G foam holds the superior averaged total EMI shielding effectiveness(EMI SET)of 75.2 dB and optimal absorption coefficient(A)of 0.93 at the incident direction from NiNWs/WPU layer,suggesting the dominant absorption in EMI shielding mechanism and efficiently alleviating the secondary electromagnetic pollution.Furthermore,n Ni-m Ni@Cu-G foam also exhibits fascinating compressive properties with a compressive strength of 49.3 kPa,which is essential for its practical application.This multilayered gradient architecture design provides valuable insight into high-efficiently constructing absorption-dominant EMI shielding composites.展开更多
Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical int...Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical integrity. MXenes, as an emerging family of two-dimensional nanomaterials, have demonstrated significant potential for enhancement modification in this area. However, achieving uniform distribution and effective utilization on a large scale with low filler content has posed a significant challenge. Herein, a highly lightweight, flexible, and functional Ti_(3)C_(2)T_(x)/ poly(3,4-ethylene-dioxythiophene) poly (styrene sulfonate) (PEDOT: PSS) /Ammonium polyphosphate (APP) reclaimed carbon fiber (rCF) veil reinforced plastics (MPA-rCFRPs) was fabricated through large-scale vacuum-assisted filtration and autoclave technology. The modified MPA-rCFRPs have exhibited substantial improvements in electromagnetic shielding with MXene additive amounts as low as 0.24 %-1.07 %, increasing the electro-magnetic interference shielding effectiveness (EMI SE) to 87.12 dB, improved by 350.02 %. Remarkably, the through-thickness electrical conductivity of MPA-rCFRPs exhibited a 767.14 % improvement, escalating from 19.73 S/m to 151.41 S/m. Meanwhile, the modified composites have exhibited enhanced photothermal, electrothermal, and flame-retardant properties, and the above improvements have not shown a significant impact on the mechanical properties of the material. This work represents a practical solution for the construction of large-scale MXene-based carbon fiber composites and opens the door to functional reutilization of rCF materials.展开更多
The rapid advancement of electronic devices and wireless communication has heightened the demand for electromagnetic interference(EMI)shielding materials to ensure electromagnetic compatibility.Transition metal carbid...The rapid advancement of electronic devices and wireless communication has heightened the demand for electromagnetic interference(EMI)shielding materials to ensure electromagnetic compatibility.Transition metal carbides/nitrides(MXenes)have emerged as promising candidates due to their outstanding electrical conductivity,large specific surface area,rich surface functionalities,and exceptional mechanical properties.These attributes make MXenes particularly advantageous when assembled into lightweight,three-dimensional(3D)porous aerogels that deliver exceptional EMI shielding performance.This review systematically discusses the fundamental mechanisms of EMI shielding,emphasizing critical influencing factors and key evaluation parameters.Recent advances in MXene-based aerogels for EMI shielding are summarized,highlighting effective component and structural design strategies.Additionally,the review explores the synergistic relationships between compositional adjustments and structural modulation in MXene-based aerogels,systematically evaluating their impact on EMI shielding performance.Finally,current challenges and future development prospects of MXene-based aerogels for EMI shielding applications are critically addressed,proposing research directions towards next-generation lightweight and highperformance shielding materials.展开更多
基金Supported by the National Natural Science Foundation of China(22378181).
文摘The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2024QE446)。
文摘With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption are urgently required.This study presents a bio-inspired hierarchical composite foam fabricated using supercritical nitrogen foaming technology.This material exhibits a honeycomb structure,with pore cell sizes controllable within a range of 30–92μm by regulating the filler.The carbon fiber felt(CFf)provides efficient reflection of electromagnetic waves,while the chloroprene rubber/carbon fiber/carbon black foam facilitates both wave absorption and temperature monitoring through its optimized conductive network.This synergistic mechanism results in an EMI shielding effectiveness(SE)of 60.06 d B with excellent temperature sensing performance(The temperature coefficient of resistance(TCR)is-2.642%/℃)in the 24–70℃ range.Notably,the material has a thermal conductivity of up to 0.159 W/(m·K),and the bio-inspired layered design enables information encryption,demonstrating the material's potential for secure communication applications.The foam also has tensile properties of up to 5.13 MPa and a tear strength of 33.02 N/mm.This biomimetic design overcomes the traditional limitations of flexible materials and provides a transformative solution for next-generation applications such as flexible electronics,aerospace systems and military equipment,which urgently need integrated electromagnetic protection,thermal management and information security.
基金financially supported by the National Natural Science Foundation of China(No.52103127)the Opening Project of the State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-10)Shaanxi Provincial Science and Technology Department(No.2025GH-YBXM-042).
文摘In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(CNT/cellulose-BN/PVA)composite.Using cellulose aerogel as a template,CNT were incorporated into the cellulose template by vertically impregnating the CNT suspension.Following the impregnation of BN/PVA and high-pressure compression,three-dimensional dual-continuous network structure was successfully constructed in the CNT/cellulose-BN/PVA composite.The comprehensive performance of the composite,including electromagnetic interference(EMI)shielding and Joule heating performance,was investigated.The results indicate that the total EMI shielding effectiveness(SE)for the CNT/cellulose-BN/PVA composite reveals similar values for electromagnetic waves incident from different directions,but totally different shielding mechanisms.For the CNT/cellulose-BN/PVA composite with three impregnation cycles of CNT,the EMI SE values exceeded 39 dB for electromagnetic waves incident from both the high-and low-CNT-content sides.93%of the microwaves were reflected when electromagnetic waves were incident from the high-CNT-content side,while the reflection coefficient decreased to 0.44 for the transverse direction.In addition,the construction of the dual-continuous network structure enabled the composite to exhibit both excellent electrical conductivity and good thermal conductivity simultaneously,endowing the material with good Joule heating performance.CNT/cellulose-BN/PVA composite films have significant potential for application as EMI shielding materials in extremely cold weather.
基金financially supported by the National Natural Science Foundation of China(52303036)the Natural Science Foundation of Guangxi(2024GXNSFBA010123)+2 种基金the International Science&Technology Innovation Cooperation Project of Sichuan Province(2024YFHZ0232)the International Science&Technology Cooperation Project of Chengdu(2021-GH03-00009-HZ)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Sklpme2023-3-18)。
文摘To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding performances remains crucial challenges.Herein,we propose a hierarchical manufacturing method that combines the use of 3D printing shear flow field and layer-by-layer assembly for fabricating the structurally customizable and multifunctional polylactic acid@graphene nanoparticle(PLA@GNs)materials.The dynamic behavior of polymer fluids is firstly explored via computational fluid dynamic simulation,and a Weissenberg number is employed to quantitatively analyze the disordered-to-ordered structural evolution of molecular chains and nanoparticles,allowing to tailor the micro-scale ordered structures.Subsequently,the macro-scale 3D architectures of PLA@GNs modules are fabricated by layer-by-layer assembly.Owing to the aligned GNs,the shielding performance reaches 41.2 d B,simultaneously accompanied by a directional thermal conductivity of 3.2 W m^(-1)K^(-1).Moreover,the potential application of 3D-printed shielding modules in specific civilian frequency bands such as 4G(1800–2100 MHz),Bluetooth(2402–2480 MHz),and 5G(3300–3800 MHz)is fully demonstrated.Overall,this work not only establishes a universal methodology about 3D printing shear flow field-driven orientation of two-dimensional nanoparticles within polymer fluids,but also gives a scientific method for advanced manufacturing of the next-generation electromagnetic functional modules for smart electronics.
基金supported by the Fundamental Research Funds for the Central Universities under No.2024KQ130the National Natural Science Foundation of China(No.52373259)。
文摘The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement of simultaneous high efficiency and low reflectivity across microwave,terahertz,and infrared spectra remains a formidable challenge.Herein,a carbonized MXene/polyimide(C-MXene/PI)aerogel material integrating a spatially coupled hierarchically anisotropic structure with stepwise conductivity gradients was constructed.Electromagnetic waves propagate through the top-down vertical disordered horizontal architecture and progressive conductivity gradient of C-MXene/PI aerogel,undergoing stepwise absorption-dissipation-re-dissipation processes.The C-MXene/PI aerogel exhibits an average electromagnetic interference(EMI)shielding effectiveness of91.0 dB in X-band and a reflection coefficient of 0.40.In the terahertz frequency band,the average EMI shielding performance reaches66.2 dB with a reflection coefficient of 0.33.Furthermore,the heterolayered porous architecture of C-MXene/PI aerogels exhibits low thermal conductivity and reduced infrared emissivity,enabling exceptional infrared stealth capability across the 2-16μm wavelength spectrum.This study provides an feasible strategy for constructing low-reflectivity multi-spectrum compatible shielding materials.
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National Natural Science Foundation of China(32201491)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)The authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1101-02”.
文摘Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.
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 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 Key Research and Development Program of China(No.2021YBF3501304)the National Natural Science Foundation of China(Nos.52371171,52222106,51971008,52121001)+1 种基金the Natural Science Foundation of Beijing Municipality(No.2212033)We thank the researchers at the Analysis&Testing Center of Beihang University for their assistance with testing.
文摘Electromagnetic interference(EMI)shielding materials with adaptive strain capability have broad applications in wearable electronic devices.However,as an important candidate,compressible conductive foam generally suffers from a reduction in EMI shielding performance during compression,which limits its application.Here,a compressible conductive aerogel with a unique conductive compensation effect is designed to solve this problem.CuS microspheres with metal-like conductivity serve as conductive compensation sites,and are chemically embedded in the skeletons of lamellar-structured carboxymethylcellulose(CMC)/MXene aerogel through Cu–S−Ti−C chemical bonds.The incorporation of CuS induces circularly-distributed interfacial polarization to enhance the attenuation of EM waves.More importantly,these CuS microspheres act as interlayer bridges to connect the upper and lower MXene/CMC layers during compression,thereby establishing numerous conductive compensation paths to offset the negative effect of thickness reduction on shielding performance.The optimized CMC/MXene/CuS aerogel shows stable EMI shielding performance during compression,and maintains a high shielding effectiveness of∼32.31 dB with increasing compressive strain.In addition,this composite aerogel exhibits good thermal insulation and sound absorption performances,achieving triple shielding functions against EM waves,heat and sound.
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 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.52271167 and U21A2064)the Key Program of Natural Science Foundation of Henan Province,China(No.242300421188)+1 种基金ZUA Innovation Fund for Graduate Education,China(No.2024CX134)Henan Key Laboratory of Aeronautical Material and Technology Open Foundation,China(No.ZHKF-240103).
文摘The development of stretchable conductors with high deformation,conductivity,and thermal conductivity using liquid metal(LM)has sparked widespread interest in the fields of flexible electronics,electromagnetic interference(EMI),and multifunctional materi-als.However,fabricating desirable shielding materials by directly coating LMs on soft polymer substrates remains a challenge because of the huge surface tension and weak wettability of LMs.In this study,Ga-based composite paste is prepared from a mixture of Ga and dia-mond nonmetallic particles through ultrasonic fragmentation.At various temperatures,the resulting LM composite putty(LMP)exhibits soft and hard properties and can thus be molded into specific shapes according to application needs.In addition,the composite can be eas-ily coated onto polymer substrates,such as thermoplastic polyurethane(TPU)elastomer.The fabricated LMP–TPU exhibits an impress-ive shape deformation capacity of 1100%,demonstrating exceptional tensile properties and achieving electromagnetic interference–shielding effectiveness of up to 52 dB.Furthermore,it retains an ultrahigh conductivity of 20000 S/m,even under a strain of 600%.This feature further makes it a highly competitive multifunctional material.
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the National Key Research and Development Program of China(2023YFD2201404)the National Natural Science Foundation of China Youth Fund(No.52103072)+2 种基金Beijing Natural Science Foundation(No.2222068)5·5 Engineering Research&Innovation Team Project of Beijing Forestry University(No:BLRC2023A02)the Regional Research Collaboration(RRC)Program-“Sustainable Industry Manufacturing Planning for Long‑term Ecosystems(SIMPLE)Hub”.
文摘Over 950 billion(about 3.8 million tons)masks have been consumed in the last four years around the world to protect human beings from COVID-19 and air pollution.However,very few of these used masks are being recycled,with the majority of them being landfilled or incinerated.To address this issue,we propose a repurposing upcycling strategy by converting these polypropylene(PP)-based waste masks to highperformance thermally conductive nanocomposites(PP@G,where G refers to graphene)with exceptional electromagnetic interference shielding property.The PP@G is fabricated by loading tannic acid onto PP fibers via electrostatic self-assembling,followed by mixing with graphene nanoplatelets(GNPs).Because this strategy enables the GNPs to form efficient thermal and electrical conduction pathways along the PP fiber surface,the PP@G shows a high thermal conductivity of 87 W m^(-1)K^(-1)and exhibits an electromagnetic interference shielding effectiveness of 88 dB(1100 dB cm^(−1)),making it potentially applicable for heat dissipation and electromagnetic shielding in advanced electronic devices.Life cycle assessment and techno-economic assessment results show that our repurposing strategy has significant advantages over existing methods in reducing environmental impacts and economic benefits.This strategy offers a facile and promising approach to upcycling/repurposing of fibrous waste plastics.
基金supported by the National Natural Science Foundation of China(Nos.52363004,51963003,and 52263003)Guizhou Provincial Science and Technology Projects(No.ZK[2022]Maj019).
文摘Exploiting high-performance absorption-dominant electromagnetic interference(EMI)shielding composites is urgently desired yet challenging for minimizing secondary electromagnetic radiation pollution.Herein,a nickel(Ni)shell was in-situ grown on a copper nanowires(CuNWs)core to greatly improve the stability of CuNWs,while maintaining excellent electrical conductivity.Afterward,Ni nanowires/Ni@Cu nanowires/graphite paper/waterborne polyurethane(NiNWs/Ni@CuNWs/graphite paper/WPU,n Ni-m Ni@Cu-G)composite foams with the multilayered gradient architectures were fabricated by a facile multi-step freeze-casting method.In the resultant composite foams,the lowly conductive porous NiNWs/WPU layer plays a role as the impedance matching layer,the moderately conductive porous Ni@CuNWs/WPU layer acts as the transition layer,and the highly conductive graphite paper layer serves as the reflection layer.Arising from the rational layout of multilayered gradient magnetic-electrical networks,n Ni-m Ni@Cu-G foam holds the superior averaged total EMI shielding effectiveness(EMI SET)of 75.2 dB and optimal absorption coefficient(A)of 0.93 at the incident direction from NiNWs/WPU layer,suggesting the dominant absorption in EMI shielding mechanism and efficiently alleviating the secondary electromagnetic pollution.Furthermore,n Ni-m Ni@Cu-G foam also exhibits fascinating compressive properties with a compressive strength of 49.3 kPa,which is essential for its practical application.This multilayered gradient architecture design provides valuable insight into high-efficiently constructing absorption-dominant EMI shielding composites.
文摘Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical integrity. MXenes, as an emerging family of two-dimensional nanomaterials, have demonstrated significant potential for enhancement modification in this area. However, achieving uniform distribution and effective utilization on a large scale with low filler content has posed a significant challenge. Herein, a highly lightweight, flexible, and functional Ti_(3)C_(2)T_(x)/ poly(3,4-ethylene-dioxythiophene) poly (styrene sulfonate) (PEDOT: PSS) /Ammonium polyphosphate (APP) reclaimed carbon fiber (rCF) veil reinforced plastics (MPA-rCFRPs) was fabricated through large-scale vacuum-assisted filtration and autoclave technology. The modified MPA-rCFRPs have exhibited substantial improvements in electromagnetic shielding with MXene additive amounts as low as 0.24 %-1.07 %, increasing the electro-magnetic interference shielding effectiveness (EMI SE) to 87.12 dB, improved by 350.02 %. Remarkably, the through-thickness electrical conductivity of MPA-rCFRPs exhibited a 767.14 % improvement, escalating from 19.73 S/m to 151.41 S/m. Meanwhile, the modified composites have exhibited enhanced photothermal, electrothermal, and flame-retardant properties, and the above improvements have not shown a significant impact on the mechanical properties of the material. This work represents a practical solution for the construction of large-scale MXene-based carbon fiber composites and opens the door to functional reutilization of rCF materials.
基金financially supported by National Natural Science Foundation of China(Nos.22422503,22205131,52203040,and 22375115)the Natural Science Foundation of Shandong Province(No.2022HYYQ-014)+6 种基金the Provincial Key Research and Development Program of Shandong(No.2024CXGC010314)the Discipline Construction Expenditure for Distinguished Young Scholars of Shandong University(No.31370089963141)the New 20 Funded Programs for University of Jinan(No.2021GXRC036)the Natural Science Foundation of Guangdong Province(No.2024A1515012626)the Distinguished Young Scholars of Shandong Province(Overseas)(No.2024HWYQ017)Qilu Young Scholar Program of Shandong University(No.11190082463085)the support of the Xiaomi Foundation/Xiaomi Young Talents Program
文摘The rapid advancement of electronic devices and wireless communication has heightened the demand for electromagnetic interference(EMI)shielding materials to ensure electromagnetic compatibility.Transition metal carbides/nitrides(MXenes)have emerged as promising candidates due to their outstanding electrical conductivity,large specific surface area,rich surface functionalities,and exceptional mechanical properties.These attributes make MXenes particularly advantageous when assembled into lightweight,three-dimensional(3D)porous aerogels that deliver exceptional EMI shielding performance.This review systematically discusses the fundamental mechanisms of EMI shielding,emphasizing critical influencing factors and key evaluation parameters.Recent advances in MXene-based aerogels for EMI shielding are summarized,highlighting effective component and structural design strategies.Additionally,the review explores the synergistic relationships between compositional adjustments and structural modulation in MXene-based aerogels,systematically evaluating their impact on EMI shielding performance.Finally,current challenges and future development prospects of MXene-based aerogels for EMI shielding applications are critically addressed,proposing research directions towards next-generation lightweight and highperformance shielding materials.
