Statistics

Percolation theory

Physics

Conductivity

Physical chemistry

Composite material

Neuroscience

Chemistry

Materials science

Monte Carlo method

Electrical conductor

Percolation threshold

Percolation (cognitive psychology)

Interphase

Mathematics

Genetics

Quantum mechanics

Volume fraction

Electrical resistivity and conductivity

Biology

Carbon

Interphase configurations affect conductive properties of carbon fibrous composites (CFCs), specifically the percolation of interphase triggers the dramatic change of conductive properties. It has been a key but unresolved issue how to capture the percolation of soft interphase interacted by anisotropic-shaped carbon fibers and its quantitative effect on the conductivity of CFCs. This work proposes a theoretical framework for the accurate predictions of the excluded volume and percolation threshold of soft interphase and the effective conductivity of CFCs. This framework contains three theoretical models: (1) a coupling scheme between the second virial coefficient theory and Monte Carlo simulations for determining the excluded volumes; (2) an excluded-volume-based percolation model for obtaining the percolation threshold of soft interphase; (3) a continuum percolation-based micromechanical model (CPMM) for predicting the effective conductivity of CFCs with spherocylindrical carbon fibers of high volume fraction and their surrounding interphase percolation. Comparison against numerical and experimental data validates that the theoretical framework can well predict these properties of CFCs. This framework can be regarded as a general scheme that is readily applicable to other core-shell networks. Furthermore, we use the framework to probe various factors effects on the percolation threshold of interphase and electrical conductivity of CFCs.

Insights into excluded volume and percolation of soft interphase and conductivity of carbon fibrous composites with core-shell networks