Enhanced electromagnetic interference shielding effectiveness of polyaniline functionalized carbon nanotubes filled polystyrene composites

Multiwall carbon nanotubes (MWCNTs)/polystyrene composites were fabricated by solution processing route using non-covalently functionalized (polyaniline coated) MWCNTs. These composites exhibit an extremely low percolation threshold (0.12 vol.% MWCNT) along with micro porosity and are found to have potential applications in the areas of electromagnetic interference (EMI) shielding and electrostatic dissipation (ESD) with an ESD time of 0.78 s and shielding effectiveness of −23.3 dB (>99 % attenuation). The EMI shielding was found to be dominated by absorption (−18.7 dB) with a nominal contribution from reflection (−4.6 dB) that can explained in terms of multiple internal reflection phenomenon driven by high conductivity and the porous structure.