Studies on novel surfactant-free polystyrene nanoparticles formed in microphase inversion

Randomly carboxylated polystyrene ionomers are insoluble in water. However, we found that when their tetrahydrofuran (THF) solutions are added into an excess of water or vice versa, the ionomer chains can undergo a microphase inversion to form surfactant free colloidal nanoparticles stable in water. In this study, a combination of static and dynamic laser light scattering (LLS) was used to study the influence of various experiment conditions, such as the initial ionomer concentration in THF, the degree of carboxylation, the type of counterion, the composition of the THF/water mixture, and the order of mixing the ionomer THF solution with water, on the formation and size distribution of the nanoparticles.