Insight into the diffusivity of particulate composites considering percolation of soft interphases around hard fillers: From spherical to polyhedral particles

Abstract The properties of particulate composites are generally conditioned by the interphase configurations in the materials, among which its percolation may trigger the change of transport properties. The three-dimensional particle with its morphology from spherical to polyhedral is used to represent the fillers in composites and the three-phase structures with hard core-soft shell networks are generated. By using the model of hard core-soft shell, the percolation of interphases in three-phase systems is simulated and an empirical function is derived to quantify the dependence of the critical percolation threshold ϕcore,c on the characteristics of multi-sized polyhedral cores and soft interphases. An analytical approximation of diffusivity that involves interphase percolation is further presented and the impact of various factors on the diffusivity of composites is predicted. The results indicate that the change of the diffusivity of composites near the percolation threshold is affected by the synergetic effect of particle morphology, fineness of fillers and interphase thickness.