Kinetics heterogenous nucleation

Thermodynamic and mechanical equilibrium on a curved vapor-liquid interface requires a certain degree of superheat in order to maintain a given curvature. Characteristics of homogeneous and heterogeneous nucleation can be estimated in the frame of classical theory of kinetics of nucleation (Volmer and Weber 1926 Earkas 1927 Becker and Doring 1935 Zel dovich 1943). The vapor temperature in the bubble Ts.b can be computed from equations (Bankoff and Flaute 1957 Cole 1974 Blander and Katz 1975 Li and Cheng 2004) for homogeneous nucleation in superheated liquids... 

For a reaction to produce a new phase, the new phase must first form (nucleate) from an existing phase or existing phases. Nudeation theory deals with how the new phase nucleates and how to predict nudeation rates. The best characterization of the present status of our understanding on nudeation is that we do not have a quantitative understanding of nudeation. The theories provide a qualitative picture, but fail in quantitative aspects. We have to rely on experiments to estimate nudeation rates, but nudeation experiments are not numerous and often not well controlled. In discussion of heterogeneous reaction kinetics and dynamics, the inability to predict nudeation rate is often the main obstacle to a quantitative understanding and prediction. The nudeation theories are... 

The kinetics of nucleation of one-component gas hydrates in aqueous solution have been analyzed by Kashchiev and Firoozabadi (2002b). Expressions were derived for the stationary rate of hydrate nucleation,./, for heterogeneous nucleation at the solution-gas interface or on solid substrates, and also for the special case of homogeneous nucleation. Kashchiev and Firoozabadi s work on the kinetics of hydrate nucleation provides a detailed examination of the mechanisms and kinetic expressions for hydrate nucleation, which are based on classical nucleation theory. Kashchiev and Firoozabadi s (2002b) work is only briefly summarized here, and for more details the reader is referred to the original references. 

In the last decade, progress has also been made with using superlattices as templates, or structure-directing agents, to kinetically control solid-state reactions. This is accomplished by allowing interdiffusion to reach completion before the occurrence of heterogeneous nucleation, thus trapping the system in the... 

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