Functional sub-micrometer core/shell hybrid particles coated with inorganic components have many promising applications as new materials based on their multiphase structures with unusual features. Herein we demonstrate a novel approach to produce such particles with potential applications in the fields of magnetic materials. PSt seed latex was prepared through emulsion polymerization. Core-shell P(St-coAm) particles with polyacryamide (PAm)-rich shell were formed through interfacial-initiated seeded emulsion polymerization. Then spherical P(St-co-ANI)/NiS sub-micrometer composites were successfully prepared by the reaction of nickelous sulfate (NiSO4) and thioacetamide (CH3CSNH2) under (CO)-C-60 gamma-irradiation at ambient temperature and pressure. P(St-co-AM)/NiS hybrid particles were confirmed with electron microscopy, X-ray diffraction and X-ray photo-electron spectroscopy. The properties of P(St-co-Am) hybrid particles were studied with UV-vis spectroscopy, photoluminescence spectroscopy and magnetic hysteresis loop analysis. (c) 2005 Elsevier Ltd. All rights reserved.