The influence of PAMAM dendrimers containing different terminal groups on the crystallization of CaCO₃

The influence of the poly(amidoamine) (PAMAM) dendrimers with different terminal groups on the crystallization of CaCO₃ in aqueous solution was studied. The crystals of CaCO₃ were analyzed by means of FTIR, XRD, SEM, respectively. The results show that the crystallization of CaCO ₃ in the presence of PAMAM dendrimer containing -COONa terminal groups at the external surface resulted in the formation of spherical vaterite crystals with the size of 1-2μm, whereas rhombohedral calcite crystals with the size of 10μm were formed in the absence of additive and in the presence of PAMAM dendrimer containing -NH₂ terminal groups. So the dendrimers with -COONa terminal groups are a kind of habit modifier and can influence on the crystal morphology and upon CaCO₃ crystallization.