Direct Synthesis of Hollow Vaterite Nanospheres from Amorphous Calcium Carbonate Nanoparticles via Phase Transformation

摘要

A new and simple method for preparation of hollow calcium carbonate nanospheres under mild conditions is developed. Hollow vaterite nanospheres are achieved by water-induced phase transformation of poly(4-sodiuna styrene sulfonate)-stabilized amorphous calcium carbonate (PSS—ACC) in water—ethanol solution at room temperature. It is found that the sizes of the resulting hollow-structured nanospheres can be easily regulated by the content of PSS and the phase transformation can be greatly affected by the ratio of water to ethanol in the mixed solvent. A combination effect of PSS and water is emphasized in this formation process. It is important to control the amounts of PSS and water in the experiments so that a large scale of hollow vaterite nanospheres with different sizes can be achieved. We suggest that the PSS—ACC particles use themselves as the templates to form the new crystallized shells, and its mechanism is also discussed.