Finite element modeling of effective permittivity in nanoporous epoxy composite filled with hollow nanosilica

The relative permittivity of nanoporous epoxy composites (NPCs) filled with hollow nanosilica is lower than that of unfilled epoxy resin. The low permittivity is considered to arise from the existence of cavity volume, but the effects of nanosilica particle shape, particle size distribution and agglomeration are not clear. In this study, the relative permittivity of an NPC filled with hollow nanosilica is modeled by using finite-element method including the above-mentioned factors. The proposed model successfully reproduces the experimentally-obtained low permittivity of NPCs. The effect of cavities is significant, while particle corner shape, particle size distribution or particle agglomeration is not dominant.