Candidate Mechanisms Responsible for Property Changes in Dielectric Nanocomposites

This contribution seeks to provide some insight for the documented changes in the electrical properties of filled polymers when the filler size is reduced to nanometric dimensions. After examining the possible underlying mechanisms, experiments are described in which composites based on a benign biphenol epoxy resin formulation are subjected to photo- and electro-luminescence studies in which the spectrum of the emitted light can be resolved as a function of formulation. It is shown that there is a red shift in the spectral peak at 600 nm as a result of the reduction of particulate size. The electroluminescence measurements are complemented by a detailed study of the internal space charge distribution in these materials, using the pulsed electroacoustic method. By examining both the internal charge distribution and dynamics, some linkage between the field-dependent electroluminescence and the changes of the internal charge in nanodielectrics can be established