Mechanisms of solvent evaporation encapsulation processes: predicting solvent evaporation rate

摘要

The organic solvent evaporation rate plays an important role in the solvent evaporation encapsulation process used to prepare microspheres. The solvent evaporation rate j_sA, which may be characterized by the permeability coefficient P of the aqueous evaporating system, is influenced by several process variable. These include: rotational speed #omega#, diameter of the stirrer d to mix the liquid, the volume of the liquid V, and the temperature T, which affects the kinematic viscosity v of fluid medium and the diffusivity D of the volatile organic species. The purpose of this study was to i) derive a relationship between P and the process variables; and Ii) verify the relationship experimentally. The resulting theoretical model may be used to evaluate the kinetics of mass loss during mcirosphere preparation.