3D numerical model for prediction of percolation threshold and piezoresistive characteristics of conductive polymer filled with CNT

As a kind of functional materials, conductive polymer matrix composites filled with carbon nanotube (CNT) has potential application in structural health monitoring. A good formula should have a low percolation threshold and high piezoresistive strain sensitivity, which are always being sought by costly and time-consuming experimental method. Up to date, there is still a lack of numerical models to predict the sharp transition moment in electrical conductivity and mechanical resistance characteristics. This paper aims to establish a three-dimensional (3D) numerical model to observe the conductive network formation, predict the percolation threshold and investigate the piezoresistive characteristics of CNT-filled polymer matrix composites. Additionally, the influence of filler size, filler shape and filler volume fraction on the percolation threshold and piezoresistive characteristics would be investigated. The modeling and numerical simulation method can not only provide theoretical guidance for such a functional composite material, but also could be used in the future study on design and preparation of other conductive composites with two fillers added to improve the piezoresistive strain sensitivity and to decrease the percolation threshold.