Molecular Dynamics Simulation and Quantum Chemical Calculations of Surfactant Having Suppression Effect on Water Trees

Abstract

Polyethylene (PE) is a hydrophobic polymeric insulating material. It has been found that adding hydrophilic additives can enhance the water tree resistance of PE. Such additives are most often surfactants that contain both hydrophobic and hydrophilic groups within their molecular structures. It is considered that a surfactant added to PE surrounds water molecules and stabilizes them. Hence, it is highly plausible that the solubilization of moisture in a supersaturated state leads to the suppression of water tree initiation in PE. In this study, we investigated the aggregation of water molecules and the orientation of surfactants toward water clusters by molecular dynamics (MD) simulation. In addition, quantum chemical calculations were performed to reveal the mechanism by which a surfactant suppresses water tree initiation. A comparison of the computational results with experiments suggests that the addition of a surfactant is extremely effective in suppressing bow-tie water trees.