Coaxial double-layer-coated multiwalled carbon nanotubes toward microwave absorption

Materials Letters (2018), 233, 203-206.

Zhao Yuhui, Zhou Zheng, Chen Guang-Xin, Li Qifang

Abstract: A novel coaxial double-layer-coated multiwalled carbon nanotube (MWCNTs) was synthesized to obtain excellent electromagnetic-wave-absorbing materials. Hydrochloric-acid-doped polyaniline (PANI) served as the first shell via in situ redox polymn. using FeCl₃ as the oxidizing agent.  The introduction of PANI effectively solved the problem in which ferroferric oxide (Fe₃O₄)-coated carbon nanotubes had poor integrity and easily fell off in the previous expt. After the reaction, the oxidizing agent directly provided Fe³⁺ and Fe²⁺ ions for the second Fe₃O₄ shell, which was deposited on the surface of hydrochloric-acid-doped PANI interlayer via copptn. The hybrid fully combined MWCNTs with prominent dielec. properties and Fe₃O₄ with outstanding magnetic properties and showed excellent electromagnetic wave absorption performance with high reflection loss (-15.65 dB at 15.45 GHz) and broad effective bandwidth (←-10 dB) of 3.5 GHz (14-17.5 GHz) at lowest thickness (1.5 mm).