Polymer nanocomposite dielectrics - the role of the interface

TLDR

The most significant difference between micron‑scale and nanoscale fillers is the tremendous increase in interfacial area in nanocomposites. Because the interfacial region is likely pivotal in controlling properties, the bonding between silica and polyethylene was characterized by FTIR, EPR, and XPS. Silica nanoparticles in polyethylene significantly raise breakdown strength and voltage endurance, lower dielectric permittivity, and modify space‑charge distribution and dynamics, indicating that the enhanced interfacial zone and particle‑polymer bonding are crucial for the improved dielectric behavior.

Abstract

The incorporation of silica nanoparticles into polyethylene increased the breakdown strength and voltage endurance significantly compared to the incorporation of micron scale fillers. In addition, dielectric spectroscopy showed a decrease in dielectric permittivity for the nanocomposite over the base polymer, and changes in the space charge distribution and dynamics have been documented. The most significant difference between micron scale and nanoscale fillers is the tremendous increase in interfacial area in nanocomposites. Because the interfacial region (interaction zone) is likely to be pivotal in controlling properties, the bonding between the silica and polyethylene was characterized using Fourier transformed infrared (FTTR) spectroscopy, electron paramagnetic resonance (EPR), and x-ray photoelectron spectroscopy (XPS). The picture which is emerging suggests that the enhanced interfacial zone, in addition to particle-polymer bonding, plays a very important role in determining the dielectric behavior of nanocomposites.