A model for kinetically controlled internal phase segregation during aerosol coagulation

In previous studies of particle growth, we have synthesized binary metal ox ide aerosols and have observed the evolution of internal phase segregation during growth of molten nanodroplets. We describe a new formulation of the aerosol general dynamic equation (GDE) that incorporates phase segregation in a binary aerosol. The model assumes that complete phase segregation is t he thermodynamically favored state, that no thermodynamic activation energy exists, and that the segregation process is kinetically controlled. We dev elop a GDE formulation that involves the solution of a distribution functio n N-n(V), where N-n(V) is the number density of aerosols with volume V and n phase domains (which we might think of as enclosures). The GDE is solved using a two-dimensional sectional model, under the assumption that the phas e coalescence of the minority phase is controlled by Brownian coagulation. For the purposes of these initial studies, the rate laws governing the encl osures (minority phase) assume a monodisperse particle size distribution. T he dynamical behavior of such a system is presented. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.