Experimental and Theoretical Investigation of Nonclassical Shear-Induced Nucleation Mechanism for Small Molecule

Crystallization is one of the majorsteps in industrial productionand environmental settings. According to thermodynamics and nucleationtheories, the crystallization kinetics can be controlled by adjustingthe temperature and concentration. The supersaturated liquid is almostalways flown into a crystallization device due to stirring, injection,or other reasons. The role of shear flow on the crystallization kinetics therefore plays a crucial role, but the precise shear-induced nucleationmechanism has so far remained elusive. Here we present a detailedmechanism for the example of glycine, and we validate it by comparingexperimental data to theory. A major result is the confirmation thatnucleation has a maximum as a function of shear, which can lead toa dramatic enhancement of industrial production.Shear rate is a key parameter in cooling crystallization;this research aims to analyze its influence in the scope of classical and nonclassical nucleation theories.