Modified nanoprecipitation method for polysulfone nanoparticles preparation.

Towards developing a more universal and productive nanoprecipitation processes, we focus on the preparation of polysulfone (PSF) nanoparticles through instantaneous solvent displacement in a metal membrane contactor between dimethylformamide (DMF) and water. In the original nanoprecipitation process, cubic nuclei can form instantaneously, but slow growth and aggregation have intensive interactions. Moreover, the reservation of DMF may enhance the adhesive effect between polymeric particles, causing severe particle aggregation. To overcome this difficulty, a modified nanoprecipitation method appending a quenching step was proposed. The well-dispersed PSF nanoparticles are successfully obtained when ethyl acetate is introduced. In this way, DMF can be extracted from water solution, thus facilitating the precipitating of PSF. Furthermore, selecting water as the continuous fluid, the particle size can be adjusted simply by tuning the operating parameters, including the PSF concentration in the dispersed fluid and the ratio of two feeds. Compared with previous reports on the continuous nanoprecipitation process for polymeric nanoparticles preparation, this work shows advantages including expanding the adaptability to more functional polymers, providing better flexibility on process or product development independent of the use of surfactant, and presenting a high throughput and easy-to-scale-up equipment platform.