Multi-walled carbon nanotube–graphene–polyaniline multiphase nanocomposite with superior electromagnetic shielding effectiveness

TLDR

The study aims to enhance EMI shielding effectiveness of polyaniline nanocomposites by employing a multiphase approach. The authors fabricated PANINGF–MWCNTs composites by incorporating natural graphite flakes into modified PANI, synthesizing multilayer graphene in situ via ball milling, and characterizing the resulting nanocomposites, noting that absorption from space‑charge polarization and reduced carrier mobility drives the high EMI shielding. TEM revealed multilayer graphene bridges PANI and MWCNTs, and the composites exhibited increasing EMI shielding up to –98 dB at 10 wt % MWCNTs, while reduced carrier mobility also raised shore hardness from 56 to 91.

Abstract

The multiphase approach was adapted to enhance the electromagnetic interference (EMI) shielding effectiveness (SE) of polyaniline (PANI) based nanocomposites. The natural graphite flakes (NGF) incorporated modified PANI was used for the development of multi-walled carbon nanotubes (MWCNTs) based nanocomposites. In PANINGF–MWCNTs composites, multilayer graphene was synthesized in situ by ball milling. The resultant PANINGF–MWCNTs nanocomposites were characterized by different techniques. It was revealed from the transmission electron microscope (TEM) observation that in situ derived multilayer graphene acts as a bridge between PANI and MWCNTs, and plays a significant role for improving the properties of multiphase nanocomposites. It was observed that EMI-SE increases with increasing the MWCNTs content from 1 to 10 wt% in the multiphase nanocomposites. The maximum value of total EMI-SE was −98 dB of nanocomposite with 10 wt% of MWCNTs content. The high value of EMI-SE is dominated by the absorption phenomenon which is due to the collective effect of increase in space charge polarization and decrease in carrier mobility. The decrease in carrier mobility has a positive effect on the shore hardness value due to the strong interaction between the reinforcing constituent in multiphase nanocomposites. As a consequence, shore hardness increases from 56 to 91 at 10 wt% of MWCNTs.