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.