Molecular Dynamics Investigation on the Diffusion of POSS in Insulating Oil Under External Electric Field

In this study, the interaction energy and migration characteristics of caged octaphenylpropyl polysilsesquioxane (POSS) molecules in vegetable insulating oil and mineral insulating oil under an external electric field are investigated. The results show that POSS molecules have a stronger migration ability in mineral oil, but the electric field has no obvious effect on the migration ability of POSS molecules in mineral oil. In addition, the electric field can promote the diffusion of POSS molecules in vegetable oil, which is caused by the increase of electrostatic interaction energy between POSS molecules and vegetable oil molecules under the electric field. Furthermore, mineral oil molecules and vegetable oil molecules have strong interaction with the Si–O structure and peripheral branches of POSS molecules, which limits the diffusion of POSS molecules in vegetable oil, and further explains the reason for the large displacement of POSS molecules in the mineral oil system. This work is of great significance to the application research of nano-additives in dielectrics.