Long-particle nucleation stage

In Stage II (referred to as Stage II to differentiate it from the classical Interval II), the rate of polymerization and the number of polymer particles continue to increase but at a slower rate. Polymer particles are formed by homogeneous nucleation as long as monomer droplets and enough emulsifier (>0.05 mM) are present in the system. The end of this stage is marked by the disappearance of monomer droplets, but particle nucleation may or may not end at this time. 

A heterogeneous reaction of the type A + B = AB necessarily begins with the nucleation of AB. Nucleation and early growth are different from the later stages of reaction as long as the number of atomic particles in the boundary region is similar to the number of those in the bulk. This means that the chemical potential of the components and the growth kinetics depend explicitly on the size and form of the nuclei. 

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