A novel mechanism of hybrid fillers on enhanced dielectric constant and suppressed dielectric loss in percolative nanocomposites

Abstract

Flexible dielectric materials with high dielectric constant (εr) and low loss (tan δ) are constantly pursued. Polymer composites filled with conductive fillers has been demonstrated ultrahigh effective dielectric constant near percolation, yet usually accompanied with high tan δ due to the formation of conductive pathway. Here, two-dimensional organically modified montmorillonite (OMMT) was introduced into the poly(vinylidene fluoride)/carbon tubes (2.0 wt %) (PVDF/CNTs) nanocomposites to block the formation of CNTs conductive pathway. The results indicate that preventing the formation of 3D conductive network over long-range distance and allowing electrons to travel freely within CNTs clusters in short-range distance is the key to enormously suppress the loss without sacrificing high dielectric constant in percolative nanocomposites. The PVDF/CNTs nanocomposites loaded 4.0 wt% OMMT is reduced by 96.2% in tan δ as well as increased by 22.7% in εr at 1000 Hz, compared to the nanocomposites without OMMT. This will provide a design principle for desired-dielectric material.