Formation of polystyrene nanoparticles with a core–shell contrast by surfactant-free emulsion polymerization and thermal annealing
Taketo Tokuda·Shin-ichi Yusa·Thi Ngan Vu·Rintaro Takahashi·Rei Kakitani·Chisato Kizaki·Hideto Minami
Abstract Styrene was polymerized by soap-free emulsion polymerization in water in the presence of an organic solvent to form polystyrene (PSt) nanoparticles containing the solvent. Thermal annealing under reflux produced particles with core–shell contrast in TEM, indicating radial redistribution of polymer mass. The core size depended on solvent type, while a higher initiator/monomer ratio reduced particle size. Internal contrast remained tunable across a range of particle sizes.