Surface‐Modified Nano‐SiO₂ in Natural Ester Insulating Oil for Enhanced Interfacial Interaction: Insights from Molecular Dynamics Simulations

Surface modifiers can significantly improve the compatibility between nanoparticles and base solutions, and are widely studied in applied materials. Here, two kinds of soybean oil‐based natural ester insulating oil models doped with surface‐modified nanoparticles (oleic acid‐SiO 2 , stearic acid‐SiO 2 ) are successfully established, and the molecular dynamics simulation accompanied with density functional theory is resorted to explore the interaction between nanoparticles and natural ester. The results reveal that the interaction between two surface‐modified nanoparticles and triglycerides is negative, demonstrating the adsorption effect, and it decreases slowly with increasing temperature. Importantly, the difference of hydrogen bond is observed. When the temperature is 383 K, the hydrogen bonds of the two models are 69.496 and 66.932 (average number), respectively. The formation of hydrogen bonds contributes to the enhancement of the thermal stability of natural ester. From the frontier molecular orbitals, it is obtained that the energy gap of oleic acid‐SiO 2 (3.996 eV) is 41% higher than stearic acid‐SiO 2 (2.832 eV), indicating that the electrons of the former are not easy to transition and resulting in a higher oxidation stability. These insights provide a strategy for revealing high‐performance natural ester insulating oil doped with surface‐modified nanoparticles, and broadening their application in power grid equipment.