Breakage of TiO2 agglomerates in electrostatically stabilized aqueous dispersions
Breakage of TiO2 agglomerates in electrostatically stabilized aqueous dispersions
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DOI：
10.1016/j.powtec.2005.08.020
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发表时间：
2005-12-06
影响因子：
5.2
通讯作者：
Druffel, T
中科院分区：
文献类型：
--
作者：
Mandzy, N;Grulke, E;Druffel, T
金属氧化物纳米颗粒在纳米复合薄膜中具有添加剂的应用。对于包括透明薄膜和涂层的光学应用，纳米颗粒应该均匀分散在聚合物薄膜中。大多数商业上可用的纳米颗粒都是最大尺寸约为1微米的大颗粒，由大小从5到50 mm的初级颗粒组成。大团聚体会散射光，不能直接用于光学系统。采用液体悬浮液超声法从工业二氧化钛纳米粉末中制备稳定的分散体。超声处理的二氧化钛纳米粉末的平均直径与比能量呈负相关。在一次快速的初始尺寸减小之后，持续的超声作用导致颗粒不明显的减小，甚至团聚。同时观察到了冲蚀和断裂机制。没有一种商业纳米粉末被成功地粉碎到它们的初级颗粒尺寸。当分散体的Zeta电位值小于-30 mV或大于+30 mV(C)2005 Elsevier B.V.时，可以通过硝酸或氢氧化铵的静电稳定来防止分散体的团聚。
Nanoparticles of metal oxides have applications as additives in thin nanocomposite films. For optical applications that include transparent films and coatings, nanoparticles should be uniformly dispersed in the polymer film. Most commercially available nanoparticles are large agglomerates about 1 mu m in maximum dimensions composed of primary particles with sizes ranging from 5 to 50 run. The large agglomerates scatter light and are not directly suitable for optical systems. Ultrasonication of liquid suspensions was used to prepare stable dispersions from commercial titania nanopowders. The mean diameter of sonicated titania nanopowders was correlated inversely to the specific energy. After a rapid initial size reduction, continued ultrasonication lead to insignificant reduction and even reagglomeration of the particles. Both erosion and fracture mechanisms were observed. None of the commercial nanopowders were successfully broken to their primary particle sizes. Reagglomeration of the dispersion could be prevented by electrostatic stabilization with nitric acid or ammonium hydroxide when its zeta potential value was less than -30 mV or greater than +30 mV (c) 2005 Elsevier B.V. All rights reserved.