Hierarchical hybrid Monte-Carlo method for simulation of two-component aerosol nucleation, coagulation and phase segregation

Abstract

In this paper we propose a Monte-Carlo method for the simulation of the simultaneous nucleation, coagulation and phase segregation of an immiscible two-component binary aerosol. The model is intended to qualitatively model our prior studies of the synthesis of mixed metal oxides for which phase segregated domains have been observed in molten nanodroplets. Our new approach generalizes our previous approach (J. Colloid Interface Sci., in press) by incorporating nucleation in addition to coagulation and phase segregation into the method. The nucleation is taken into account using a hierarchy of computational volumes represented in the simulation. Our attempts to model only the coagulation of heterogeneous aerosols using basic statistics of their internal state (J. Aerosol Sci., to appear; Chem. Eng. Sci. 56 (2001) 5763; J. Nanoparticle Res., in press) introduced some limitations. Using Monte-Carlo approaches, on the other hand, we can model the system of heterogeneous aerosols without any a priori assumption. The Monte-Carlo results show that the growth of the minor phase can be moderated quite dramatically by small changes in system temperature, which effectively serves to change the viscosity of the major phase and therefore the Brownian transport properties of the minor phase.