New insights into Crystallization: From Thermodynamics to Polymorphism and Kinetics
A new technique has been successfully developed to overcome the difficulty in measuring thermodynamic activities for supersaturated electrolyte-containing solutions so as to provide new insights into crystallization. Using the new technique, thermodynamic activities for NaCl+glycine+H2O solutions and other systems were measured. The analysis of the measured activities revealed that univalent cations and anions would generally inhibit alpha-glycine and promote gamma-glycine polymorph, leading to the systematic investigation of the impact of different electrolytes on glycine polymorphs. The obtained results of glycine polymorphs were well interpreted by the proposed mechanisms which were further supported by the experimental kinetic data of gamma-glycine crystal growth, highlighting that the valences rather than other properties of the cations and anions primarily determine the outcome of glycine polymorphs. The potential application of the proposed mechanisms was also discussed to explore a new mean of polymorphism control and crystallization enhancement for many other crystalline substances.
crystallization, thermodynamics, polymorphism, kinetics, supersaturated solution, electrolyte
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