The effect of filler distribution in the enhancement of the energy storage in nanocomposites*

Mixing dielectric polymers with high permittivity nano-sized inclusions affects their electrical properties. These nanocomposites are extensively used in actuation applications via employing electrostriction properties of the matrix, and in electrostatic energy storage applications employing high polarization fields of the fillers. In both cases existing theoretical studies mostly utilize mixing rule approaches that consider a homogeneous filler distribution in the matrix. Consequently, the effective permittivity of the composite never exceeds the the permittivity of the filler. We show that much higher effective permittivities can be achieved by manipulating the morphology of the inclusion distribution in the matrix. Simulation results for the field distribution reveal an enhancement of the field localization and dipole-dipole correlation effects in some proposed morphologies. By considering several possible clustering scenarios we found that a cylindrical clustering along the applied field has a potential to achieve an order of magnitude increase in the effective permittivity. The issue of chained filler configurations which lower the breakdown field threshold for the material is also addressed.