A procedure was developed to coat functionalized polystyrene spheres with well-defined layer of amorphous titanium dioxide. The core-shell particles can be turned into TiO2 nanosponge by calcining the dried particles in a furnace. The phase transformation temperature of TiO2 hybrid microspheres from anatase to rutile was increased by about 200 degrees C due to the blocking function of the calcined polymer remainder. (C) 2008 Elsevier B.V. All rights reserved.