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(70f) Multivariate Population Balance Models for Nanoparticle Stabilization by Copolymer Assembly

Cheng, C., Iowa State University
Fox, R. O., Iowa State University
Vigil, R. D., Iowa State University

Nanoprecipitation [1] is a process to produce functional nanoparticles stabilized by amphiphilic copolymer directed assembly. In this process, organic drug and copolymers are dissolved in solvent and rapidly mixed with nonsolvent in a customized micro-device to create high supersaturation. The growth of nanoparticles is kinetically arrested by block copolymer assembly on the surface of the organic drug, and therefore a tunable and narrow particle size distribution is achievable. In order to simulate the Nanoprecipitation process, the population balance equations (PBEs) are solved to obtain the particle size distribution (PSD) information in the particulate flow system. A multivariate PBE model was presented to describe the particle stabilization process. In this model, organic particle and copolymer are denoted by A-type and B-type particles, respectively, where A-type and B-type can aggregate until the cluster is ?deactivated.? By assigning a limit number of B-type monomers in a cluster, the growth of particle is arrested while the B-type particle reaches its maximum number. In this work, the PBEs of different types of particles are also solved with the quadrature method of moments (QMOM) [2] to obtain faster computation expenses and the results (mean particle size) are compared with experimental data.

[1] B. K. Johnson and R. K. Prud'homme. Flash nanoprecipitation of organic

actives and block copolymers using a confined impinging jets mixer. Australian

Journal Of Chemistry, 56(10):1021?1024, 2003.

[2] Marchisio, D. L. & Fox, R. O.

Solution of population balance equations using the direct quadrature method of moments

Journal Of Aerosol Science, 2005, 36, 43-73