Population balance model development and experimental validation for the heteroaggregation of oppositely charged micro- and nano-particles

The properties of heteroaggregates (aggregates of particles that are different in various aspects such as size, surface charge) depend on the properties of the particles along with the initial relative concentration of the particles. In this article, the heteroaggregation of two different types of oppositely charged hydrogel particles, alginate microparticles and chitosan nanoparticles were studied. A population balance model (PBM), popularly used to model particulate processes was developed based on the inter-particle interactions such as van der Waals, electrostatic and hydration in order to study the effect of initial relative concentration of alginate and chitosan on the final heteroaggregate size distribution. The presence of three different regimes (namely, 'dispersed, uncoated', 'agglomerated' and 'dispersed, coated') based on the initial concentration of alginate and chitosan was observed both from the model calculations and the experiments. In addition, to better understand these interactions, the effect of various process parameters on the aggregation kinetics were studied.