In this article we describe the combined use of gamma-irradiation initiated micro-emulsion polymerization and redox interfacial-initiated micro-emulsion polymerization to prepare hollow polystyrene micro-spheres with movable CdS nanoparticles inside (CdS@PSt) hybrid materials under room temperature and ambient pressure. First, mono-dispersed CdS nanoparticles with diameters 50 nm were synthesized in inversed micro-emulsion under gamma-irradiation. Then, CdS nanoparticles were coated with PSt via interfacial-initiated micro-emulsion polymerization with cumene hydroperoxide/ferrous sulfate (CHPO-Fe2+) as the redox initiation pair. The resulted CdS@PSt hybrid materials were identified by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS) and X-ray powder diffraction (XRD). (C) 2008 Wiley Periodicals, Inc.