Preparation of polymer nanocapsules for use as carriers via one-step redox interfacially initiated miniemulsion polymerization

In this work, one-step redox interfacially initiated miniemulsion polymerization (IMEP) was employed to fabricate polystyrene (PS) nanocapsules 80 nm in diameter with a 2,2′-bipyridine core by the redox-initiated coupling of cumene hydroperoxide (CHPO) to iron(II) sulfate (FS) using waterborne polyurethane (WPU) as surfactant and hexadecane (HD) as costabilizer. The morphology of the nanocapsules was characterized by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Dynamic light scattering (DLS) was used to determine the size and polydispersity of the nanocapsules. It was found that the latexes prepared by miniemulsion polymerization via the redox-initiated method had relatively small diameters (40–100 nm) and a relatively narrow particle size distribution index (PDI: 0.086–0.124), which indicated that polymeric nanoparticles with small diameters and a narrow PDI can easily be prepared via one-step IMEP. The release of 2,2′-bipyridine from the nanocapsules was monitored by UV-visible spectroscopy. These results indicate that polymeric nanocapsules with a functional liquid core can be successfully fabricated via IMEP.