Facile preparation of CaCO3 nanocrystals with unique morphologies controlled by supramolecular complexes

A facile and effective method to synthesize dendrite-shaped calcium carbonate (CaCO3) nanocrystals in aqueous solutions of dodecyltrimethylammonium bromide (DTAB) and beta-cyclodextrin (beta-CD) is reported. It has been demonstrated that the supramolecular host-guest complexes formed by DTAB and beta-CD play a key role in the fabrication of these unique CaCO3 nanocrystals. In order to systematically study the effect of the cationic surfactant, 1-dodecyl-3-methylimidazolium bromide (C(12)mimBr) and didodecyltrimethylammonium bromide (DDAB) were also used. The results show that the structures of the complexes formed by different cationic surfactants with beta-CD have a strong impact on the final morphologies of the CaCO3 nanocrystals. Moreover, the interaction energies between beta-CD and cationic surfactant molecules were calculated using molecular mechanics, and a possible mechanism for the formation of CaCO3 nanocrystals was proposed.