Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO3 nanoparticles for energy storage applications

A facile surface hydroxylation treatment using hydrogen peroxide to modify the surface of BaTiO3 nanofillers dispersed in a ferroelectric copolymer host has been investigated. We demonstrate that the surface functionalization of the BaTiO3 nanofillers (< 100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity and breakdown strength of the thin-film nanocomposites. Surface modified BaTiO3 particles display better dispersion within the polymer matrix, resulting in enhanced relative permittivity and reduced dielectric loss. The dielectric behavior of the nanocomposite films containing up to 30 vol.% BaTiO3 agreed well with the Bruggeman model. These results demonstrate the potential of facile surface hydroxylation of nanoparticles towards the fabrication of higher energy-density nanocomposites.