Phase specific dispersion of functional nanoparticles in soft nanocomposites resulting in enhanced electromagnetic screening ability dominated by absorption

Abstract

The effect of phase specific localisation of MWNTs (multiwalled carbon nanotubes) and magnetic FeNi (iron–nickel) alloy particles on bulk electrical conductivity and electromagnetic (EM) wave attenuation was investigated in biphasic co-continuous blends of PVDF/SMA (polyvinylidene fluoride/styrene maleic anhydride). It is envisaged that packing different functional nanoparticles in a given phase of a co-continuous blend can impede the charge transport phenomenon and the overall dispersion state. Therefore, phase specific localisation can facilitate the tuning of the functional properties in biphasic blends. This strategy was adopted here wherein conducting MWNTs and magnetic FeNi particles were surface tailored to position them in different phases during processing. As the functional particles prefer the PVDF phase by virtue of thermodynamics, by harnessing amine functional moieties on the surface, their localisation can be tuned to position them in the SMA phase (due to amine–anhydride coupling). This was achieved by sequential mixing during processing. For the best combination, SE_T was observed to be −23 dB when MWNTs were localised in the SMA phase and magnetic particles in the PVDF phase of the blend with an impressive 92% absorption of the incident EM radiation.