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

摘要

Flexible dielectric materials with high dielectric constant (& epsilon;r) and low loss (tan & delta;) are constantly pursued. Polymer composites filled with conductive fillers has been demonstrated ultrahigh effective dielectric constant near percolation, yet usually accompanied with high tan & delta; 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 & delta; as well as increased by 22.7% in & epsilon;r at 1000 Hz, compared to the nanocomposites without OMMT. This will provide a design principle for desired-dielectric material.

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