writer：Qi Li, Lijie Dong, Wei Deng, Qingming Zhu, Yun Liu, Chuanxi Xiong
keywords：CaCO3 NPs，solvent-free nanofluid，nanostructures
source：期刊
Issue time：2009年

  It is reported that the aqueous slurry of CaCO^₃ NPs has a basic pH of 9.4, and under ambient conditions, CaCO₃ has OH groups on the surface. The pH value was adjusted to 10-12 in our synthesis procedure so that more OH groups would be attached to the incompletely coordinated calcium ions on the surface, and a basic pH of ∼10.5 was proven to be favorable in promoting the condensation of OH groups on other inorganic particles surfaces. By investigating the X-ray photoelectron spectroscopy (XPS) of C1s and Ca2p core levels from CaCO₃ NPs both before and after adjusting the pH value, we found surface differences in the two cases. Under an adjusted pH value, we successfully synthesized the solvent-free fluids based on CaCO₃ NPs in a facile and user friendly method. Since we can only obtain a solid-like product based on CaCO₃ NPs without adjusting the pH value, it can be concluded that the pH adjustment is effectual.