Abstract:

The ordered arrays of titanium dioxide（TiO₂）and polystyrene（PS）core-shell microspheres were prepared from composite suspensions of TiO₂ colloidal particles with nanometer size and polystyrene colloidal particles with submicron size by using the vertical co-deposition method.By this way，the preparation and assembly of core-shell microspheres could be realized synchronously.This kind of ordered arrays of core-shell microspheres had many special optical properties，such as generating a complete band-gap.After removing the PS colloidal crystal template，ordered arrays of hollow TiO₂ microspheres were formed.The effect of the volume ratio（R）of PS to TiO₂ colloidal particles on the formation of ordered arrays was investigated.The results showed that a proper volume ratio R（6∶1）was of importance to the formation of ordered arrays of hollow microspheres.When R was lower than 6∶1，an unconnected macroporous structure would be generated.On the contrary，when R was higher than 6∶1，neither the macroporous structure nor the ordered arrays of hollow microspheres could be fabricated.Furthermore，the comparative experiment of the immersed infiltration method showed that the formation of hollow TiO₂ microspheres should be caused by the shrinkage of nanometer TiO₂ spheres during the crystal transformation of TiO₂ materials.