Modeling the percolation behavior of conductive particles/insulating polymer-based composites with equivalent circuit of resistance

Abstract

In conductive particle/insulating polymer composites, percolation behavior significantly affects their electrical properties. Based on particle concentration, the composites are classified into rich and poor regions. A theoretical model consisting of four parts has been developed to describe the entire process in which the shape of the rich regions evolves from spheres to ellipsoids, barrels, and finally cylinders as particle concentration increases. To determine electrical properties and percolation behavior of composites, different theoretical methods are employed. Specifically, the percolation threshold is identified by detecting the abnormal increase in the composite conductivity slope. Below this threshold, electrical properties are calculated using homogenization theory; after it, the equivalent circuit method is applied. Based on this model, key electrical parameters like conductivity, resistivity, and leakage current are computed for composites with carbon-based, metallic, and ferromagnetic particles in different polymer matrices. Results show good agreement between theoretical predictions and experimental data. Moreover, the study also explores the impacts of particle distribution, component properties, and interface thickness on percolation behavior, and discusses its double-percolation behaviors. This model offers new insights for predicting percolation behavior and opens up new perspectives for revealing electrical properties of this composite.