Molecular Simulation on the Local Morphology and Electronic Behavior of PE/SiO2Nanocomposite

The addition of nanocomposites to polyethylene (PE) is proving to be an effective and promising method for improving the electrical and dielectric properties of PE. However, the mechanisms of how such nanoparticles could influence the morphological and electrical properties of PE remain largely unknown, especially at the molecular level. To understand this fundamental aspect, nano-sized PE/SiO
2
composite molecular models and their interfaces were employed to study the local morphological characteristics and electrical properties across the interface using Molecular Dynamics and Density Functional Theory. We found that the local density of PE fluctuates within a certain distance between SiO
2
and PE bulk as a result of attractive interactions between PE molecules and SiO
2
nanoparticles. The diffusion behavior of PE atoms as well as the Gauche and Anti-Gauche defects distributions as a function of distance from SiO
2
could be attributed to density fluctuations in PE. In addition, the potential barrier between SiO
2
and PE was calculated using PBE and PBE0 hybrid functionals for both (1 0 0) and (0 0 1) surfaces of SiO
2
. Both electrons and holes are subject to potential barriers of greater than 0.97 eV across both interfaces. Our findings provide insight into the impact of nanoparticles on the local molecular morphology and electronic behavior of insulating materials, which may assist in the design of novel nanocomposite insulating materials used for high voltage insulation.