Cationic and anionic PSt (polystyrene) latexes were synthesized using emulsion polymerization.The anionic PSt particles were treated using -aminopropyl triethoxysilane (KH550) and the surface of the particles in this anionic latex was thus changed from negatively to positively charged.PSt/TiO2 composite particles were then prepared through hydrolysis of TBT (tetrabutyl titanate) in a mixture of ethanol and water

in the presence of the above 3 types of PSt latex particles

respectively

i.e.anionic PSt

cationic PSt and the anionic PSt particles treated using KH550. Results showed that a clear PSt/TiO2 core-shell structure was obtained only by using the KH550 treated anionic PSt particles.When these core-shell composite particles were dispersed into tetrahydrofuran to dissolve PSt core

TiO2 hollow particles were clearly observed under TEM.The study on the influence of KH550 amount on PSt/TiO2 core-shell formation revealed that 0.1 g of KH550 was enough to change the anionic PSt particles from negatively to positively charged

more KH550 did not contribute to the formation of PSt/TiO2 core-shell particles.Using 5 mL of the KH550 treated PSt latex of 9.4% solids

appropriate amount of TBT should be controlled between 1 g to 2 g in order to get well formed TiO2 hollow particles.The mechanisms of the PSt/TiO2 core-shell formation and of TiO2 hollow particles were discussed.