NUCLEATION AND GROWTH IN SUPERSATURATED MONOLAYERS

A nucleation-growth collision theory has been surveyed which can describe the transformation kinetics for formation and growth of three-dimensional centers from supersaturated monolayers theoretically. The models are based on the following key features: (i) single-step nucleation and subsequent growth of the nuclei, (ii) the total transformation rate as convolution of nucleation rate and growth rate, and (iii) overlapping of the-growing centres. Two models are reviewed, the first one for the limiting cases of nucleation and growth with assumed geometric shape and the second one for nucleation according to the exponential law and the formation of lenticular centers from a supersaturated monolayer. In the more general second model, the effect of the interfacial tensions at the three-phase contact air/water/center is allowed for both the contact angles of the lenticular center. Application on experimental data enables the determination of nucleation rate constants. Manifold experimental evidence is provided for the adequacy of the nucleation-growth collision theory.