Crystallization and Self-Assembly of Calcium Carbonate Architectures

Shape-controlled crystallization and self-assembly of high-ordered CaCO 3 architectures were realized by using soluble starch as structure directing agents in aqueous solution. Mushrooms, dumbbells, spheres, and truncated-octahedron CaCO 3 crystals composed of spindly microcrystals were obtained by tuning the experimental parameters, such as the concentration of starch, pH value, and the concentration of Ca 2+ cations. The phases, morphologies, and structures of the products were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and infrared spectrophotometry. The surface properties of CaCO 3 crystals were also successfully modified to be hydrophobic using n -dodecanethiol as a modifier. The contact angle changed from 23° to 137° and 148° after surface treatment. The hydrophobic properties of the resulting products may have potential applications as a filler in composite materials.