A method to prepare submicron-sized porous titanium oxide (TiO2) particles is studied in this work. Polystyrene (PS) template particles were prepared by emulsifier-free emulsion polymerization. The polymer templates dispersed in the aqueous solution have been used for entrapping titanium(IV) isopropoxide (TTIP), by the swelling process in a suitable solvent mixture containing a swelling solvent (good solvent or poor solvent), a TiO2 precursor (TTIP), and a chelating agent (AcAc), within the polymer templates, followed by hydrolysis/condensation reaction of TTIP confined in PS template particles by the addition of the chelating agent. The influence of various reaction parameters, such as mixtures of different weight ratios between the PS particles and desiccative nu, AcAc amounts, and the swelling solvent amounts and type, on the size, bulk, and composition of the particles was investigated. Porous TiO2 particles have been prepared by thermal decomposition of the PS templates at 500 degrees C. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.