Study of dielectric properties of meta-aramid fibers by molecular dynamics methods using modified OPLSAA force field

The dielectric properties of materials have been a prevalent subject in dielectric physics research. However, the theoretical calculation of the dielectric properties of polymer insulating materials remains challenging. Taking meta-aramid fiber (PMIA) as the research object, the micro-dielectric relaxation process of the PMIA system was studied by molecular dynamics and the polarization frequency response theory. The OPLSAA force field was optimized based on the density functional theory B3LYP/6-31G. Using calculations of the spatial structure, chain motion, basic physical and chemical properties, and dielectric properties of PMIA, it was found that the optimized OPLSAA force field accurately indicated the dielectric properties of PMIA. The frequency-dependent dielectric properties of PMIA calculated by the optimized OPLSAA force field were consistent with the polarization frequency response theory, and the simulation results agreed with the Debye model theory. The theoretical calculation process of polymer dielectric properties based on molecular dynamics presented in this paper provides a new avenue to improve the prediction accuracy of polymer dielectric properties.