Multi-walled carbon nanotubes/polyaniline composites with negative permittivity and negative permeability

Intrinsic double negative metamaterials have been found in metal particles/ceramic composites, but polymer composites haven't achieved negative permittivity and negative permeability simultaneously until now. Negative permittivity and negative permeability appear simultaneously in multi-walled carbon nanotubes (MWCNTs)/polyaniline (PANI) composites in present study. No significant change in chemical bond and crystallization is found in MWCNTs/PANI composites through ATR and XRD tests. It is found from SEM analysis that MWCNTs/PANI composites form different morphology with the increase of MWCNT content. Occurrence of negative permittivity and permeability in MWCNTs/PANI composites derives for conductive network, closed circuit structure of MWCNTs and MWCNTs/PANI composite particles. The double negative property appears in the frequency range 955-1000 MHz in 40 wt% MWCNTs/PANI composites, 930-1000 MHz in 50 wt% MWCNTs/PANI composites, 925-1000 MHz in 60 wt% MWCNTs/PANI composites and 915-1000 MHz in 70 wt% MWCNTs/PANI composites. This study makes the properties of metamaterials no longer only depend on specific combination of structures, thus possesses great significance on research and development of metamaterials. (C) 2016 Elsevier Ltd. All rights reserved.