Preparation of nanomaterials having hierarchical structure based on self-organization

Abstract

We report the spontaneous formation of polymer nanoparticles from a clear solution, containing a poor nonvolatile solvent, by the slow evaporation of a good volatile solvent. After evaporation, polymer nanoparticles with homogeneous shape and size are dispersed in the poor solvent. The homogeneous nucleation and successive growth of particles emerge during the dynamic nonequilibrium process of solvent evaporation. Because of the physical generality of the particle formation mechanism, this procedure is applicable to a wide variety of polymers. A block copolymer, which forms a lamella structure in its bulk film, is used in this study. Compared with particle sizes obtained by the reprecipitation method, the size of particles prepared by our method is uniform. A piled-up lamella structure is formed in the spherical polymer nanoparticle.