Filler Dependencies of Electrical Conductivity in Nanotube and Nanofiber Composites

TL;DR

This paper introduces a model for predicting the electrical conductivity of nanotube and nanofiber polymer composites by considering microscopic filler features and electron tunneling, providing formulas for practical property tailoring.

Contribution

The paper presents a new analytical model that links microscopic filler characteristics to composite conductivity using the critical path method, applicable to various nanocomposite systems.

Findings

Model accurately predicts conductivity based on filler parameters.

Reinterprets experimental data to validate the model.

Extracts characteristic tunneling length consistent with expectations.

Abstract

We report on a model of polymer nanocomposites with fibrous fillers which explicitly considers the microscopic filler features and replicates the composites as random distributions of particles interconnected via electron tunneling. By exploiting the critical path method, we are able to obtain simple formulas, applicable to most nanotube and nanofiber composites, which allow to infer the overall composite conductivity starting from few parameters like filler volume fraction, size, and aspect-ratio. The validity of our formulation is assessed by reinterpreting existing experimental results and by extracting the characteristic tunneling length, which is mostly found within its expected value range. These results can be used practically to tailor the electrical properties of nanocomposites.