Nucleation experiments

Chen et al. [92] also performed self-nucleation experiments by DSC in PB-fr-PEO diblock copolymers and PB/PB-b-PEO blends. The cooling scans presented in their work showed that a classical self-nucleation behavior was obtained for PEO homopolymer and for the PB/PB-b-PEO blend where the weight fraction of PEO was 0.64 and the morphology was lamellar in the melt. For PB/PB-fr-PEO blends with cylinder or sphere morphology, the crystallization temperature remained nearly constant for several self-seeding temperatures evaluated. This observation indicates that domain II or the self-nucleation domain was not observable for these systems, as expected in view of the general trend outlined earlier. 

The application of FTIR extinction spectroscopy to study composition and phase changes during a typical AIDA ice nucleation experiment is shown in Figure 4. The left panel shows a series of FTIR extinction spectra recorded during an AIDA expansion experiment... 

Acknowledement The nucleation experiments have been done under the support by the Ministry of Education, Science and Culture, Grant-in-Aid for Special Project Research No.62113004. The authors also thank Mr. A. Yamano of DAINIPPON SCREEN MFG Co. Ltd. for his cooperation. 

Two effects are observed in homogeneous nucleation experiments for all substances. First, the nucleation rate is always a steep function of saturation ratio S. The second feature common to all systems is that the critical saturation ratio Sc decreases as T increases, and J increases as T increases at constant S. Also, critical nuclei become smaller as 5 increases and as T increases. 

---