Study of precipitation reactions by X-ray microscopy: CaCO3 precipitation and the effect of polycarboxylates

A fundamental understanding of precipitation reactions is based on informat ion about the structural evolution of the system on all length scales and s tarting at the beginning of the reaction. We introduce X-ray microscopy as an additional analytical tool in order to achieve this understanding. X-ray microscopy combines high resolution (down to 40 mo) and experiments at amb ient pressure. The latter point allows the study of colloidal systems withi n the water phase and the performance of time-resolved microscopy. Taking C aCO3 precipitation as a model system, it is shown how further knowledge can be obtained on the dynamics of structure formation. We discuss the followi ng points: formation and recrystallization of precursors; transient stabili zation of CaCO3 nanoparticles by polycarboxylates; dependence of the struct ure evolution (stabilization or recrystallization) on the polymer concentra tion.