Abstract: Peanut-like CaCO₃ assemblies with core-shell structure were obtained in polyacrylamide aqueous solution. The as-prepared products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results indicate that the peanut-like CaCO₃ assemblies has some hollows. The shell of the CaCO₃ assemblies is composed of calcite rhombohedras, and the core of the CaCO₃ assemblies is composed of rod-like aggregates which are assembled by small particles and the core has a radially outward growth structure. The radially outward structure of the core is explained by the fractal growth theory, and the formation of Core/Shell structure is explained by the Ostwald ripening theory.

Key words: Core/Shell, CaCO₃, fractal growth, ripening