A submicrometer-scaled polystyrene/melamine-formaldehyde hollow microsphere composite was prepared by self-assembling of sulfonated polystyrene (SPS) latex particles at the interface Of emulsion droplets and then being fixed in place, using a hard melamine-formaldehyde (MF) composite layer. For control-released purposes, the influential factors that control the size and uniformity of the packed-droplets and the permeability of the composite shell. including the initial particle location, the hydrophilicity and the size of colloidal templates, the oil phase solvent and reserving, time of emulsions after the addition of MF prepolymer, were further studied. Relatively uniform sized particle packed-drop lets with an average diameter of 10 mu m were obtained. The assembled SIPS particles kept ordering and minimal contamination after the preparation of composite microspheres. which allows of controlling the permeability from the interstices between the particles. Porous-mesh-structured MF composite layer was formed to further control the permeability. The morphology of emulsions and composite microspheres were characterized by optical microscopy. scanning and transmission electron microscopy. (c) 2006 Elsevier Inc. All rights reserved.