Nucleation, athermal heterogeneous

For athermal nucleation (self-seeding nucleatiOTi as a special case of heterogeneous nucleation), the number of nuclei is fixed. Thus the number of spherulites is fixed, with a density mlV, = Anr 3, r = vt, and then... 

In immiscible polymer blends with a high degree of immiscibility such as PP/PS, it has been shown that nucleation at the interface affects the crystallization behavior. Wenig et al. (1990) showed that with increasing the amount of PS in a blend with PP, the nucleation shifted from preferentially thermal (related to the degree of undercooling) to more athermal. This was explained by the effect of heterogeneous surface nucleation at PS interfaces (Fig. 3.53). 

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