Evidence for the role of the interface in polyolefin nanocomposites

The burgeoning area of nanodielectrics has been fueled by the demonstration of enhanced electrical and mechanical properties observed in nanoparticle filled polymers. The high surface energy and vastly augmented surface area (in comparison to conventional composites) is thought to be the underlying reason for such benefits. This paper explores the electrical properties of silicon dioxide nanoparticle/low-density cross-linked polyethylene matrix composites and the effect of the large interface on breakdown strength with both polar and non-polar surface treatments. To that end, the interface was characterized to examine the species and bonding present, and dielectric spectroscopy used to highlight the interfacial polarization. Significantly enhanced dielectric breakdown strength was observed relative to conventional microcomposites, and some speculation about the mechanism responsible is offered.