Facile fabrication of polymer nanocapsules by microemulsion polymerization

Abstract

Polystyrene and polyacrylonitrile nanocapsules were obtained using microemulsion polymerization and the diameters of hollow spheres were ca. 20 nm ~ 70 nm. The separation of polymer phase from the non-solvent phase lead to hollow morphology of polymer and the size of polystyrene nanocapsules could be controlled by using different surfactants spacers due to micellar characteristics of surfactants. Surfactants used in microemulsion could be removed by excess methanol and isooctane in a core part was dried at room temperature. To investigate the components of the polymer materials at each step, FT-IR and EDAX analysis were performed. The morphology and size distribution of the nanospheres were measured by FE-SEM and TEM. From these analysis and results, the following conclusions can be derived. The size of polystyrene nanocapsules formed in this system decreases as the surfactant with shorter hydrocarbon chain lengths is used. When a radical initiator, KPS is used, The particle size for the SDS system is larger than DTAB system. Due to the insolubility of polyacrylonitrile in the monomer, The shape of polyacrylonitrile nanocapsules shows crumpled appearance.