The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure....The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure.Notably,fluoridizing engineering can meet these requirements by regulating the material morphology,defect distribution,surface polarization and forming hydrophobic structures.In this study,we designed a combined oxidation-fluoridizing method to obtain an electromagnetic wave ab-sorbing and superhydrophobic material,namely,fluoridizing graphene@copper(F-GE@Cu)hybrids with multi-interfacial heterostructures.This strategy involved the oxidation of graphene-wrapped Cu nanopar-ticles(GE@Cu)prepared by the thermal decomposition of cupric tartrate to GE@Cu_(x) O(x=1 and 2)and further fluorination by PTFE pyrolysis to obtain F-GE@Cu with a yolk-shell structure.Multi-interfacial heterostructures were achieved using precise modulation of the Cu particle,carbon-cladding layer,and fluoridizing products such as CuF_(2) and fluorinated graphene(FGE),this resulted in improved interfacial polarization and impedance matching to achieve satisfactory broadband and electromagnetic wave loss performance.Consequently,the as-prepared fluorinated graphene@copper fluoride(FGE@CuF_(2))exhibited high performance for electromagnetic wave(EMW)absorption with an intense reflection loss(RLmin)of−53.0 dB and a broad effective bandwidth(EAB)of 8.9 GHz(9.1-18.0 GHz).Additionally,the FGE cladding conferred the hybrids with excellent superhydrophobic properties(WAC=154.0°),allowing it to tolerate diverse and harsh water-containing environments,providing the microwave-absorbing coatings with a universal waterproofing capability.This study presents a new strategy for preparing multifunctional elec-tromagnetic wave-absorbing materials.展开更多
Magnetic expanded graphite(EG)hybrids were synthesized by co-intercalation polymerization of aniline together with transition metal ions.Experimental results show that metal ions(Fe,Co,Ni,Cu)and even their mixtures ca...Magnetic expanded graphite(EG)hybrids were synthesized by co-intercalation polymerization of aniline together with transition metal ions.Experimental results show that metal ions(Fe,Co,Ni,Cu)and even their mixtures can co-intercalate into graphite interlayers with flexibly controllable ratios and contents.Among these co-intercalation compounds,Fe/Ni-intercalated graphite with a predesigned mole ratio of 1:3 transforms into NiFe_(2)O_(4)/FeNi_(3)@EG during the annealing process.The synthesized magnetic EG hybrids present multiband microwave absorption in C and X bands due to improved impedance match as well as significantly enhanced interfacial polarization relaxation induced by multi-componential metals.The reflection values of−39.1 dB at 6.95 GHz and−25.7 dB at 9.4 GHz are achieved with an ultra-low loading of 5 wt.%.This work provides a flexible approach for tuning the components and structures of magnetic EG hybrids,which may contribute to the development of microwave absorption materials with superior performances.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51573149)。
文摘The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure.Notably,fluoridizing engineering can meet these requirements by regulating the material morphology,defect distribution,surface polarization and forming hydrophobic structures.In this study,we designed a combined oxidation-fluoridizing method to obtain an electromagnetic wave ab-sorbing and superhydrophobic material,namely,fluoridizing graphene@copper(F-GE@Cu)hybrids with multi-interfacial heterostructures.This strategy involved the oxidation of graphene-wrapped Cu nanopar-ticles(GE@Cu)prepared by the thermal decomposition of cupric tartrate to GE@Cu_(x) O(x=1 and 2)and further fluorination by PTFE pyrolysis to obtain F-GE@Cu with a yolk-shell structure.Multi-interfacial heterostructures were achieved using precise modulation of the Cu particle,carbon-cladding layer,and fluoridizing products such as CuF_(2) and fluorinated graphene(FGE),this resulted in improved interfacial polarization and impedance matching to achieve satisfactory broadband and electromagnetic wave loss performance.Consequently,the as-prepared fluorinated graphene@copper fluoride(FGE@CuF_(2))exhibited high performance for electromagnetic wave(EMW)absorption with an intense reflection loss(RLmin)of−53.0 dB and a broad effective bandwidth(EAB)of 8.9 GHz(9.1-18.0 GHz).Additionally,the FGE cladding conferred the hybrids with excellent superhydrophobic properties(WAC=154.0°),allowing it to tolerate diverse and harsh water-containing environments,providing the microwave-absorbing coatings with a universal waterproofing capability.This study presents a new strategy for preparing multifunctional elec-tromagnetic wave-absorbing materials.
基金the financial support of the National Natural Science Foundation of China(No.51573149)the Key R&D Projects in Sichuan Province(Nos.2020ZDZX0005 and 2020ZDZX0008).
文摘Magnetic expanded graphite(EG)hybrids were synthesized by co-intercalation polymerization of aniline together with transition metal ions.Experimental results show that metal ions(Fe,Co,Ni,Cu)and even their mixtures can co-intercalate into graphite interlayers with flexibly controllable ratios and contents.Among these co-intercalation compounds,Fe/Ni-intercalated graphite with a predesigned mole ratio of 1:3 transforms into NiFe_(2)O_(4)/FeNi_(3)@EG during the annealing process.The synthesized magnetic EG hybrids present multiband microwave absorption in C and X bands due to improved impedance match as well as significantly enhanced interfacial polarization relaxation induced by multi-componential metals.The reflection values of−39.1 dB at 6.95 GHz and−25.7 dB at 9.4 GHz are achieved with an ultra-low loading of 5 wt.%.This work provides a flexible approach for tuning the components and structures of magnetic EG hybrids,which may contribute to the development of microwave absorption materials with superior performances.
