Towards an understanding of piezoresistivity in filled polymer composites

Filled polymer composites are capable of combining the favourable mechanical properties of polymers with desirable electrical properties of filler particles. Carbon-black elastomer nanocomposites are capable of conducting electricity while maintaining high stretchability. Despite these materials having been studied and utilised for a number of decades, the relationship between their internal structure and their macroscopic properties is still not fully understood. A major feature of their behaviour is significant piezoresistivity, which can be a nuisance in certain applications and a benefit in others. It is known that there is a relationship between the piezoresistivity of the material and the percolation threshold. However, the exact mechanisms underlying this behaviour are not rigorously understood. This work utilises Monte Carlo modelling to propose and examine ways in which the structure of the internal nanoparticle network, and the evolution of said network with strain could help to explain the piezoresistivity of these materials. Hopefully, a more detailed understanding of this mechanism will lead to an improved capability to customise it for various applications.