Estimating of contact area among carbon nanofibers in nanocomposites by the features of network, tunnel and interphase

A larger contact area (S) among the nanoparticles significantly enhances electron transfer within nanocomposites; however, S remains an indeterminate factor. In this paper, two innovative models for the conductivity of carbon nanofiber (CNF) polymer samples (PCNFs) are integrated to express S as a function of various parameters, including CNF concentration, waviness, percolation onset, CNF dimensions, interphase depth, network fraction, and tunneling diameter. Extensive experimental conductivity data substantiate the robustness of the proposed models. Moreover, the influence of each parameter on S is systematically analyzed to validate the developed equation. The highest contact area is achieved by the maximum CNF concentration, the thinnest and longest nanofibers, minimal waviness, the densest interphase, and the highest network fraction. Specifically, S value of 1400 nm² is observed with a contact number of 200 and a percolation onset () of 0.002, whereas the contact area diminishes to zero at = 0.03. Thus, a greater number of contacts and a lower percolation onset are favorable to increase the contact area, while minimal contacts and a higher percolation onset result in the absence of contact area.