Hollow particles are produced by the burying of sulfate end-groups inside particles prepared by emulsion polymerization of styrene with potassium persulfate as initiator in the absence/presence of a nonionic emulsifier

We resolved the longtime enigma in emulsion polymerization of styrene with K₂S₂O₈by showing the fact that hollow polystyrene particles were successfully prepared by heat treatment in the emulsion state.