Synthesis of Polystyrene Nanocapsules by Redox Interface-Initiated Inversed Microemulsion Polymerization for Drug Release

Polystyrene nanocapsules with a diameter of 140 nm and a water-soluble sodium salicylate core were prepared by redox interface-initiated emulsion polymerization (RIEP) in an inversed microemulsion with cumene hydroperoxide/iron (II) sulfate as the redox initiation couple. The morphology of the nanocapsules was characterized by transmission electron microscopy and field emission scanning electron microscopy. Dynamic light scattering was used to determine the nanocapsule size and polydispersity (0.14-0.20). The release of sodium salicylate from the nanocapsules was monitored by ultraviolet-visible spectroscopy. All of the results indicate that the fabrication of core-shell nanocapsules with the water-soluble active chemical as the core via RIEP was successful. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1630-1634, 2010