Molecular modelling for nanocomposite dielectrics
Low loss electric energy transportation research with focus on insulating materials is the main issue here. Insulating nanocomposites have experimentally been shown to have improved electrical properties as compared with pure polymer materials. The cause of these improvements is not yet fully understood. Existing electrochemical models don't capture electro-dynamical behavior. These models introduce an interfacial region between nanoparticle and polymer, and such zones have been observed in experiments. The interfacial region is often referred to as the main cause of good performance of nanocomposites as insulating materials. We compare the electronic structure of the interfacial region in the polyethylene magnesium oxide nanocomposite with the electronic structures of its bulk constituents. We utilize density functional theory (implemented in VASP) to investigate changes of the energy band gap in comparison with its pure constituents. Polyethylene in combination with different oxide nanoparticles was chosen as a material of study. With application of periodic boundaries the system of consideration represents a 2d-periodic structure, i.e. a thin infinite sheet of the interfacial region between the polyethylene and the nanoparticle. We investigate the existence of defect states at the interface between the materials by computing the density of states for different systems.