Nucleation-catalysis-kinetics analysis under dynamic conditions.
Even at large undercooling, nucleation during solidification is usually controlled by a heterogeneous process. A number of models have been devised to describe the catalytic potency of various potential nucleation sites. Most common analysis models are based upon continuum descriptions that neglect the atomistic structural features that are important at the critical nucleus size scale. Even when surface structures such as steps are considered, they are treated as static stationary features in catalysis models. At the same time, nucleation is recognized as a dynamic process. Experimental strategies to explore some aspects of nucleation dynamics have been developed based upon the droplet method. In droplet dispersions, heterogeneous catalysis can be examined in two-phase liquid-solid mixtures with well-characterized morphologies to reveal surface structure effects and catalyst dynamics.