Modelling dynamics of dispersion of nanoscale particle clusters

Abstract

A modelling approach to predict and enhance understanding of the dispersion phenomenon is presented. The discrete/distinct element method (DEM) is adopted to study the behaviour of single linear and spherical agglomerates, immersed in a simple shear flow field, in response to shearing under steady or dynamic/oscillatory flow conditions. The effects of hydrodynamic forces, which result from both the straining and rotating components of the flow, and cohesive forces of interaction, comprised of short range van der Waals attractive and Born repulsive forces, are considered. Simulations of simplified linear agglomerates demonstrate the ease with which the simulation can probe the fundamental effects of varying types of interaction forces. Comparative results of the three-dimensional simulation of the dispersion of spherical nanosize silica agglomerates in response to steady and unsteady shearing are found to be in good agreement with reported experimental trends. The current model allows probing and prediction of the dispersion phenomenon as a function of processing conditions, agglomerate structure/morphology and material properties and interaction forces.