A corrected phase-field breakdown model of the nano-Al₂O₃/epoxy resin composite considering interfacial molecular configuration and barrier height

Abstract The phase-field (PF) method is commonly used for modeling phase transitions in materials. The evolution of electrical trees in dielectric materials represents a typical phase transition process. However, in the case of dielectric nanocomposites, the interfacial region plays a crucial role in overall performance but has been largely overlooked in PF modeling. In this study, we propose a corrected PF model by incorporating an interfacial layer. Specifically, in the nano-Al 2 O 3 /epoxy resin (ER) composite, an interfacial layer that considers interfacial molecular configuration and barrier height is applied on the surface of nanoparticles. The evolution of the electrical tree is investigated across different filler contents. Furthermore, corresponding ER composites are prepared and tested to assess their insulating properties. Experimental results align well with simulation models, showing higher dielectric strength in the 0.1 vol% sample. The localized distortion of the electric field stands out as a key factor driving the evolution of electrical trees, a phenomenon that our synergistically modified PF model accurately captures. This work offers a more precise and dependable approach to modeling the evolution of electrical trees, thereby enhancing theoretical guidance for predicting the dielectric strength of nanocomposites.