SIMULATION OF PERCOLATION IN NANOCOMPOSITE MATERIALS SYSTEMS

Abstract

In this thesis, a classic Monte Carlo simulation is developed to study percolation behaviour in disordered systems for objects in both two and three dimensions. In two dimensions (2D), the simulation examines the impact of sticks with preferential orientation, polydisperse length, and clustering on the percolation threshold. The model system utilises randomly dispersed sticks on a 2D plane. The results for each scenario are summarised as functions of various dependence parameters: the orientation parameter e, the coefficient of variation (CV) of stick length, and the stick cluster intensity Y. In three dimensions (3D), the simulation employs fundamental objects like spheres, rods, and discs to investigate the influence of structure on percolation. The focus is on carbon-based nanoparticles such as carbon black (CB), nanotubes (CNT), and graphite nanoplate (GNP) dispersed in a polymer matrix. The geometric percolation threshold is formulated as a function of the object’s aspect ratio, specifically for rods. For structures like discs, aerographite shapes, and spheres cluster, the effective aspect ratio characterises the structures and is related to the percolation threshold. In addition to single-filler systems, binary blend structures and their dependence on aspect ratio are examined and captured through their weighted aspect ratio. Moreover, the concentration of objects above the percolation threshold is determined using a resistor network to predict the critical exponent t for various 3D structures. The simulation results offer statistical insights into percolation behaviour in disordered systems and have the potential to inform the design of materials for specific applications.

Date of Award	31 Dec 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	William Sampson (Supervisor) & Ian Kinloch (Supervisor)