Abstract: Monodisperse cubic BaTiO₃ nanocrystallines coated by oleic acid were synthesized through solvothermal method, and the average size of the nanoparticals was 6.0 nm. The microstructure of BaTiO₃ nanocrystallines was characterized by the techniques of XRD and TEM, while the effects of the length of alcohol chain, the content of oleic acid and heat treatment temperature on the phase composition and morphology of BaTiO₃ were also investigated. The result shows that the as-prepared nanoparticals have small size, narrow size distribution and good monodispersity, and the surfaces of which are nonpolar and can be dissolved in nonpolar solvent. Because the surfaces of nanocrystallines are coated by oleophilic long alkyl chain, they are incompatible with water surroundings to form some repulsion. With the coaction of gravity and repulsion, nanocrystallines can be separated effectively from liquid phase environment.

Key words: Barium titanate, Monodisperse nanocrystals, Controlled synthesis