Non-Isocyanate Polyurethane Nanoprecipitation: toward an Optimized Preparation of Poly(hydroxy)urethane Nanoparticles

Abstract This study describes the influence of different parameters on the production of original monodisperse and stable poly(hydroxy)urethane (PHU) nanoparticles with a size inferior to 100 nm by nanoprecipitation. DMSO and SDS were used as polymer solvent and surfactant respectively. Nanosuspensions were characterized by dynamic light scattering (DLS) and cryo-transmission electronic microscopy (cryo-TEM). A 23 full-factorial design was employed to study the main effects and interaction effects of three independent variables − polymer concentration in the organic phase (X1), water volume (X2) and surfactant concentration in the aqueous phase (X3) − on two responses – particle size (Y1) and size distribution (Y2). The results allowed to determine the experimental conditions favouring the smallest diameter or the narrowest size distribution. The critical micellar concentration value of SDS in various water-solvent mixtures helped to highlight the role of the surfactant in the PHU nanosuspension characteristics and stability. The results showed that the use of surfactant was mandatory for nanosuspension stabilization, but the presence of numerous surfactant micelles induced nanoparticle aggregation. Finally, the ageing study evidenced that nanosuspensions with the lowest size distribution were the most stable over time.