PS/TiO_2核壳型微球和空心TiO_2微球有序排列的制备

Preparation of ordered arrays of PS/TiO_2 core-shell microspheres and hollow TiO_2 microspheres

利用纳米级二氧化钛(TiO2)溶胶微粒与聚苯乙烯(PS)胶体颗粒的混合悬浮液,以垂直共沉积的方法制备了核壳型PS/TiO2微球的有序排列。当利用煅烧的方法去除PS胶粒晶体模板后,可以形成空心TiO2微球的三维有序排列。考察了混合悬浮液中两种胶体颗粒的体积比(PS∶TiO2=R)对空心TiO2微球有序排列形成的影响。实验结果表明,合适的R值(6∶1)对于空心微球有序排列的形成至关重要。与此同时,浸渍填充法对照实验的结果表明,煅烧过程中TiO2纳米颗粒晶型转化引起的收缩是造成TiO2空心球产生的主要原因。

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 bandgap. 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.