Influence of the Mole Ratio of the Interacting to the Stabilizing Portion (RI/S) in Hyperbranched Polymers on CaCO₃Crystallization: Synthesis of Highly Monodisperse Microspheres

This work investigates the influence of the mole ratio of the interacting to the stabilizing portion ( R I/S ) in hyperbranched polymers on the morphology and the polymorph evolution of CaCO 3 . The R I/S is defined as the mole ratio of the carboxyl units (interacting portion) to the glycerol units (stabilizing portion) in carboxyl-terminated hyperbranched polyglycerol (HPG-COOH) and can be changed systematically from 0.1 to 0.9. Especially, when it is above 0.5, highly monodisperse CaCO 3 microspheres are first prepared by direct mixing of Ca 2+ and CO 3 2– in the presence of HPG-COOH. Our results demonstrate the topology effect of the hyperbranched polymers on the crystallization of CaCO 3 and suggest that both the conformation of the stabilizing portion and the density and the distribution of the interacting portion determine the roles of HPG-COOH in CaCO 3 crystallization, such as the calcium-binding ability, the face-selective interaction with crystals, and the inhibition of CaCO 3 nucleation and growth.