Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shieldin...Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shielding materials(i.e.,when the EM wave is incident from different sides of the sample,the EMI shielding effectiveness(SE)is rather different)are strongly required;unfortunately,no comprehensive literature report is available on this research field.Herein,Nicoated melamine foams(Ni@MF)were obtained by a facile electroless plating process,and multiwalled carbon nanotube(CNT)papers were prepared via a simple vacuum-assisted self-assembly approach.Then,step-wise asymmetric poly(butylene adipate-co-terephthalate)(PBAT)composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation approach.The step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding performances.When the EM wave is incident from Ni@MF layer or CNT layer,Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE(SET)of 38.3 and 29.5 dB,respectively,which illustrates theΔSET of 8.8 dB.This work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures,which has promising applications in portable electronics and next-generation communication technologies.展开更多
Along with the integrated and miniaturized development of advanced electronic devices,phase change materials(PCMs)simultaneously with efficient thermal management and high electromag-netic interference(EMI)shielding e...Along with the integrated and miniaturized development of advanced electronic devices,phase change materials(PCMs)simultaneously with efficient thermal management and high electromag-netic interference(EMI)shielding effectiveness(SE)are ungently demanded.Herein,the shape-stabilized MXene/Ni-platted melamine sponge/Regenerated cellulose/Graphene nanoplate/Polyethylene glycol(MX/Ni@MS/RCG/PEG)composite PCMs comprising hierarchical Ni@MS/RCG and MXene film were fabricated via a facile encapsulation approach.Hierarchical Ni@MS/RCG hybrid aerogel was prepared by electroless plating and sol-gel methods,and MXene film was obtained using vacuum-assisted filtra-tion procedure.The synergistic effect of conductive Ni@MS/RCG networks and tight MXene film endows MX/Ni@MS/RCG/PEG composite PCMs with good shape stability,high cyclic reliability,large latent heat of phase change(154.3 J g^(–1)),excellent thermal conductivity(TC,0.47 W m^(–1)K^(–1))and favorable EMI shield-ing performance(32.7 dB).The TC of acceptable 0.47 W m^(–1)K^(–1)is observed for MX/Ni@MS/RCG-5/PEG at a rather low GNP content of merely 0.39 wt%.In addition,the temperature variation of MX/Ni@MS/RCG-5/PEG is a lot faster than that of pure PEG in the heating/cooling process,revealing the remarkable energy storage and release efficiency for the composite PCMs.This investigation has taken an important step to-wards shape-stabilized composite PCMs with both effective thermal management and high EMI SE for promising applications in electronic packaging and advanced energy.展开更多
基金Science and Technology Plan Project of Guizhou Province(No.[2019]1084 and[2018]5781)National Natural Science Foundation of China(No.51963003)+3 种基金The Youth Science and Technology Talent Growth Project of Guizhou Province Education Department(No.[2018]106)Outstanding Youth Program of Guizhou Province(No.20170439178)The Key project of Fundamental research in Guizhou province[2020]1Z044Scientific Research Project of Introduced Talents of Guizhou University(No.(2017)07)are acknowledged for the financial support.
文摘Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shielding materials(i.e.,when the EM wave is incident from different sides of the sample,the EMI shielding effectiveness(SE)is rather different)are strongly required;unfortunately,no comprehensive literature report is available on this research field.Herein,Nicoated melamine foams(Ni@MF)were obtained by a facile electroless plating process,and multiwalled carbon nanotube(CNT)papers were prepared via a simple vacuum-assisted self-assembly approach.Then,step-wise asymmetric poly(butylene adipate-co-terephthalate)(PBAT)composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation approach.The step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding performances.When the EM wave is incident from Ni@MF layer or CNT layer,Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE(SET)of 38.3 and 29.5 dB,respectively,which illustrates theΔSET of 8.8 dB.This work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures,which has promising applications in portable electronics and next-generation communication technologies.
基金supported by the National Natural Science Foundation of China(No.51963003)the Science and Tech-nology Plan Project of Guizhou Province(No.ZK[2022]Maj019)+1 种基金the Youth Science and Technology Talent Growth Project of Guizhou Province Education Department(No.[2018]106)the Key Project of Fundamental Research in Guizhou Province(No.[2020]1Z044).
文摘Along with the integrated and miniaturized development of advanced electronic devices,phase change materials(PCMs)simultaneously with efficient thermal management and high electromag-netic interference(EMI)shielding effectiveness(SE)are ungently demanded.Herein,the shape-stabilized MXene/Ni-platted melamine sponge/Regenerated cellulose/Graphene nanoplate/Polyethylene glycol(MX/Ni@MS/RCG/PEG)composite PCMs comprising hierarchical Ni@MS/RCG and MXene film were fabricated via a facile encapsulation approach.Hierarchical Ni@MS/RCG hybrid aerogel was prepared by electroless plating and sol-gel methods,and MXene film was obtained using vacuum-assisted filtra-tion procedure.The synergistic effect of conductive Ni@MS/RCG networks and tight MXene film endows MX/Ni@MS/RCG/PEG composite PCMs with good shape stability,high cyclic reliability,large latent heat of phase change(154.3 J g^(–1)),excellent thermal conductivity(TC,0.47 W m^(–1)K^(–1))and favorable EMI shield-ing performance(32.7 dB).The TC of acceptable 0.47 W m^(–1)K^(–1)is observed for MX/Ni@MS/RCG-5/PEG at a rather low GNP content of merely 0.39 wt%.In addition,the temperature variation of MX/Ni@MS/RCG-5/PEG is a lot faster than that of pure PEG in the heating/cooling process,revealing the remarkable energy storage and release efficiency for the composite PCMs.This investigation has taken an important step to-wards shape-stabilized composite PCMs with both effective thermal management and high EMI SE for promising applications in electronic packaging and advanced energy.