Fabrication of size-controlled polyimide nanoparticles

Polyimide particles were fabricated through the two-steps imidization of poly(amic acid) particles prepared by using reprecipitation method. PAA and PI nanoparticles were all spherical, and the changes of particle size, its distribution, and morphology were not observed before and after the imidization. The preparation of PI nanoparticles size-controlled between ca. 20-500 nm was also achieved by changing the experimental conditions, temperature of the poor solvent, the composition of two kind of poor solvent, and PAA-NMP solution concentration.