Crystallization in Monodisperse Emulsions with Particles in Size Range 20–200 nm - Food Colloids: Self-Assembly and Material Science - page 409

10000 3

1000

2

100

10 1

1

0

0.1

0.01 -1

0 100 200 300

Time / min

Figure 9 The quantity ln[(1/ f ) - 1] versus time (points) for the various sets of data in
Figures 4, 6, 7 and 8, together with the corresponding plots of temperature
against time (lines). Solid squares and solid line, 130-nm Tween 20; solid
triangles and dashed line, 320-nm Caflon2; solid circles and dotted line, 130-nm
PGE; open circles and dotted-dashed line, 123-nm Caflon1

that, at least in the case of the Caflon-stabilized emulsions, nucleation is
dominated by surface heterogeneous nucleation. We do not have sufficient
data to draw firm conclusions regarding the other surfactants.
Examination of Figure 9 indicates that the nucleation kinetics analysis is
insufficient to explain our data. Figure 6 also indicates a very complicated
situation where the melting behaviour strongly suggests that the PGE has at
least partly dissolved into the bulk oil, modifying both the surface and the bulk
properties. Beginning with crystallization at label 1, we note from Figure 9 that
there appear to be two stages of crystallization, with an initially faster rate,
slowing down below 38% solids until the limit of resolution of the technique
is reached. In the case of the other emulsions, the opposite is true with
crystallization accelerating until complete. Perhaps the PGE acts as a nucleator
and a crystal growth inhibitor, a type of behaviour known for other catalytic
nucleators. 18 Label 2 of Figure 6 indicates initiation of crystal melting. As