Fabrication of unique cage-like polystyrene particles having lots of dents on the surface via unstable seeded dispersion polymerization

Unique, hollow, micron-sized polystyrene (PS) particles having lots of dents on the surface, so-called cage-like particles, were obtained by seeded dispersion polymerization of 2-ethylhexyl methacrylate with PS particles stabilized by poly(vinyl alcohol) in the presence of hexadecane droplets. The effect of main parameters (e.g., average molecular weight of seed particles, and stabilizer and initiator type) responsible for acquiring such particles was investigated. The experimental results revealed that cage-like shape is produced because of particle coagulation during polymerization. Moreover, it was observed that changing stabilizer and initiator type, and employing seed particles with low average molecular weight, which all of them contribute in coagulation of particles, result in the fabrication of cage-like shape.