Hybridization of oxidized MWNT and silver powder in polyurethane matrix for electromagnetic interference shielding application

Yoon Jin Kim, Kyung Jin An, Kwang S. Suh, Hyung Do Choi, Jong Hwa Kwon, Yeon Choon Chung, Woo Nyon Kim, Ae Kyung Lee, Jae Ick Choi, Ho Gyu Yoon

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Multiwalled carbon nanotubes (MWNTs) are chemically modified with respect to various different oxidative conditions, including the acid concentration, treatment time, and temperature. The conductivity of polyurethane (PU) composites filled with the MWNTs oxidized under optimal condition is measured as a function of frequency with the content of MWNTs and analyzed using percolation theory. Because the PU composites filled only with the MWNTs cannot satisfy the requirements for materials providing shielding against electromagnetic waves, conductive polymer composites are fabricated by the hybridization of MWNTs with Ag flakes. It is observed that a small amount of the MWNTs remarkably enhances the conductivity and shielding effectiveness of the MWNT/Ag flake/PU composites, by bridging the gap between the flaky Ag clusters. The electromagnetic interference shielding effectiveness of the composites can be controlled from about 60 dB to more than 80 dB at an extremely low loading level of both the MWNTs and the Ag flakes in the frequency range from 10 to 1000 MHz.

Original languageEnglish
Pages (from-to)872-879
Number of pages8
JournalIEEE Transactions on Electromagnetic Compatibility
Issue number4
Publication statusPublished - 2005 Nov


  • Carbon nanotubes (CNTs)
  • Electrical properties
  • Electromagnetic interference (EMI) shielding effectiveness
  • Hybridization
  • Oxidation

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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