Cooling light scattering

Under nitrogen, 2,2 -bipyridine (0.322 g, 2.07 mmol) was added to a mixture of Ni(COD)2 (0.570 g, 2.07 mmol) in anhydrous DMF (18 mL) and the mixture was stirred at room temperature for 1 h. Then 95 (0.510 g, 1.60 mmol) was added and the reaction mixture was stirred at 60-70°C for 28 h. After cooling to room temperature, HC1 (100 mL, 2 M) was added and the mixture was stirred overnight. After filtration, the solid was washed with a mixture of MeOH (60 mL) and concentrated HC1 (10 mL), a warm aqueous solution of ethylene-diaminetetraacetic acid (EDTA) (pH 9, then pH 3), dilute ammonia, water, and MeOH repeatedly and dried under vacuum for 20 h at 80°C. Polymer 96 was obtained in 100% yield (0.261 g). Light scattering gave Mw = 5400. 

Figure 5. Light scattering plots for PVB in MIBK/MeOH mixtures at room temperature. All data were taken on solutions which had been heated for at least 2 hours at no less than 50 C. For the 1 1 and 9 1 MIBK/MeOH solvents, only the most concentrated solution was heated. Immediately after cooling, the most concentrated solution was used to prepare the solutions of lower concentration by dilution.

Hence, from the previously described light-scattering study of caseinate self-assembly in solution, we can postulate that heating/cooling not only alters the nature and strength of the physical (hydrophobic) interactions between emulsion droplets covered by caseinate. It most likely also transforms the nanoscale structural characteristics of the protein network in the bulk and at the interface, thereby affecting the viscoelastic and microstructural properties of the emulsions. 

Experimentally nucleation rates can be determined in expansion chambers [35], The vapor is expanded in a fast and practically adiabatic process. Then it cools down. Since at low temperatures, the equilibrium vapor pressure is much lower, supersaturation is reached. Partially, this is compensated for by the pressure reduction during the expansion, but the temperature effect dominates. The density of nuclei can be measured by light scattering. 

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