Kinetics of Droplet Growth in Liquid–Liquid Phase Separation of Polymer–Diluent Systems: Model Development

Abstract

A new model is presented for describing the increase in average droplet size as a function of time for systems composed of diluent droplets in a polymer–diluent matrix phase. The new model describes the merging of any two dropletsandaccounts for the effect that two coalescing drops has on neighboring drops. In particular, as two drops coalesce, fluid is expelled from between them. This expelled fluid causes the movement of neighboring drops, which leads to further coalescence of drops. The model predicts a strong influence of the droplet growth rate on the volume fraction of the droplet phase, which corresponds with experimental observations. The model was found to be sensitive to the matrix phase viscosity and the single fitting parameter, and less sensitive to the interfacial tension and Hamaker constant.