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

Flexible dielectric materials with high dielectric constant ( ε r ) 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 ε r at 1000 Hz, compared to the nanocomposites without OMMT. This will provide a design principle for desired-dielectric material.