Fabrication of Flowerlike Vaterite Calcium Carbonate Crystal Aggregates by Self-Assembly in Water/Ethanol Mixtures

Vaterite calcium carbonate hierarchical structures with a flowerlike appearance have been successfully synthesized by means of a nanoparticle‐mediated self‐organization process in an ethanol/water mixed solution system under mild conditions without using any organic additives. A mechanism for the formation of vaterite crystal aggregates with flowerlike structures made of decussate “cigars” is presented. There are two points that play important roles in the regular organization of the terminal products: one is the concentration of carbonate, and the other is the volume ratio of ethanol/double‐distilled water. In view of the results, a nanoparticle‐mediated self‐organization process is helpful in controlling the aggregation‐driven formation of complex higher‐order‐structured materials and will provide new insights into biomineralization mechanisms. This study could provide an additional tool for designing advanced materials and could be used for the synthesis of more complex crystalline three‐dimensional structures. Vaterite crystal aggregates with flowerlike morphology have been successfully synthesized by means of a nanoparticle‐mediated self‐organization process without using any organic additives.