A simple methodology to predict the tunneling conductivity of polymer/CNT nanocomposites by the roles of tunneling distance, interphase and CNT waviness
In this work, a simple methodology is presented that describes the main tunneling conductivity of polymer/CNT nanocomposites (PCNT) assuming the tunneling distance, interphase surrounding the CNT, and CNT waviness. The conductivity related to the tunneling distance is obtained by a simple equation, and its role is considered by using an extended CNT (including CNT and the tunneling space). Additionally, the effects of the interphase and CNT waviness on the percolation threshold, effective filler fraction, and percentages of percolated CNT are expressed by simple equations. The suggested model is evaluated by experimental results and the influences of CNTs and interphase parameters on the conductivity are plotted and justified. The predictions demonstrate good agreement with the experimental results, which allow the estimation of percolation threshold, interphase thickness, and tunneling distance. The conductivity changes from 0 to 350 S m−1 at different parameter ranges, where the best conductivity is obtained by the smallest waviness and the shortest tunneling distance. Generally, the high concentration of thin, long, straight, and super-conductive CNT, thick interphase, dense network, short tunneling distance, and poor percolation threshold present desirable conductivity.