• 文献标题:   High porosity scaffold composites of graphene and carbon nanotubes as microwave absorbing materials
  • 文献类型:   Article
  • 作  者:   GONZALEZ M, BASELGA J, POZUELO J
  • 作者关键词:  
  • 出版物名称:   JOURNAL OF MATERIALS CHEMISTRY C
  • ISSN:   2050-7526 EI 2050-7534
  • 通讯作者地址:   Univ Carlos III Madrid
  • 被引频次:   20
  • DOI:   10.1039/c6tc01984f
  • 出版年:   2016

▎ 摘  要

The design of microwave absorbing materials requires low reflection and high absorption of radiation simultaneously. Low reflection of electromagnetic waves can be achieved inducing porous faces which minimize the impedance mismatch. High absorption can be obtained by increasing the conductivity of the material. We report the preparation of highly porous scaffolds from a combination of graphene and carbon nanotubes. The bimodal porous structure was controlled making use of the surface properties of graphene oxide that are able to stabilize hexane droplets in aqueous dispersions of graphene oxide and carbon nanotubes. After hydrothermal and two step freeze-drying processes, macro-(220 microns) and mesoporous (10 microns) structures, due to hexane droplets and freeze drying, respectively, were obtained. DC conductivities of 8.2, 14.7, 33.2, and 60.7 S m(-1) were obtained for graphene scaffolds containing 0, 10, 20 and 40% of carbon nanotubes respectively. An electromagnetic characterization was performed on scaffolds infiltrated with epoxy resin; using appropriate models, the electromagnetic properties of the conducting phase have been obtained. Scaffolds with a thickness of 9 mm were able to absorb up to 80% of the incident radiation keeping the reflection as low as 20%.