Modeling and Simulation of Nanoparticles Formation Process: A Diffusive Approach

In this work the modeling and simulation of nanoparticle formation according to the technique of nanoprecipitation was done. In this method, the particle is formed due to the further diffusion of solvent into the aqueous phase, resulting in the aggregation of the associated polymer chains. In order to predict the characteristics of the nanoparticle and also to improve the process, it was developed a mathematical model that considers: (a) the type of polymer; (b) interaction between solvent and polymer; and, (c) dynamics of solvent diffusion. The diffusivity between polymer-solvent was modeled according to the Vrentas & Duda Free Volume Theory, including the Sanchez-Lacombe equation-of-state. The model was written in terms of Partial Differential Equation, and solved with MAPLE (R) for a given initial size. Additionally, it is a moving boundary problem because the diffusion of the solvent out of the droplet leads to its size reduction. In this work only the diffusion behavior of one droplet was considered. The dynamic simulation shows both the evolution of the solvent inside the droplet and the variation of size in time.