Facile Synthesis of Monodispersed Cubic and Spherical Calcite Nanoparticles in the Presence of Cetyltrimethylammonium Bromide.

We report the synthesis of monodisperse calcium carbonate (CaCO3) (nano)particles having either a cubic or spherical structure by reacting calcium nitrate with either sodium carbonate or citric acid, respectively, in the presence of cetyltrimethylammonium bromide (CTAB) via the sonication method. For comparison, CaCO3 (nano)particles were synthesized by the same method in the absence of CTAB and also via the standard hydrothermal method using CTAB. The synthesized CaCO3 (nano)particles were analyzed by various physico-chemical characterization techniques such as X-ray diffraction (XRD), Fourier transform infra-red spectroscopy, thermogravimetric analysis, and scanning electron microscopy with energy-dispersive spectrometer. It was found that the CaCO3 (nano)particles were highly pure with high crystallinity and exhibited the calcite polymorph phase as revealed by the XRD analysis. In addition, the analytical results showed that the (nano)particles prepared in the presence of CTAB by the sonication method had high structural ordering and no agglomeration as compared to the (nano)particles prepared by the hydrothermal method. Therefore, our sonication method is a new way to prepare shape-controlled CaCO3 (nano)particles under mild reaction conditions.