Enhancing dielectric and mechanical properties of PVDF for high-voltage insulation via nano-SiO2 modification: a molecular dynamics insight

Abstract

With the increasing demand for enhanced insulation material performance in high-voltage power equipment, polyvinylidene fluoride (PVDF) has emerged as a focal point of research due to its superior dielectric strength and broad temperature stability. However, addressing its issues with space charge accumulation and mechanical fatigue under prolonged electric field exposure remains an urgent challenge. This study systematically investigates the microscopic coupling mechanism of nano-SiO2 modified PVDF using molecular dynamics simulations. The findings indicate that SiO2 nanoparticles (2 wt.%) can significantly enhance the elastic modulus by 4.1% and the shear modulus by 21.8%, while causing a minor reduction of 1% in cohesive energy density through interfacial physical cross-linking and rigidity enhancement effects. Under electric field conditions, the C-F dipole orientation and Maxwell–Wagner interface polarization collectively drive a substantial increase in the dielectric constant. Additionally, the static electrical strength is improved by 6.3% via defect passivation and space charge trapping. A moderate rise in free volume fraction (3.7%) optimizes material flexibility and mitigates microcrack propagation. This study elucidates the crucial role of nano-modification engineering in balancing dielectric loss and mechanical stability, providing atomic-scale theoretical support for the design of advanced high-voltage insulating materials.