I. Creaming Behavior

Kinetics of Cream Formation by the Mechanism of Consolidation in Flocculating Emulsions

“…[7]) can be found if one realizes that att = 0 the spatial gradient of φ has not yet been developed in the emulsion volume, and the term ∂ p/∂z then drops off from Eq. [3]. Since att = 0 the boundary starts moving with velocity (dH/dt)| t=0 = −u| t=0 , Eqs.…”

“…Since att = 0 the boundary starts moving with velocity (dH/dt)| t=0 = −u| t=0 , Eqs. [3] and [6] yield…”

“…However, it is still realistic because the characteristic velocity of particle motion, U 0 = (2 ρga 2 )/(9η), is relatively high, e.g., about 6.5 × 10 −4 cm/s for a sphere with radius a = 5 µm, with ρ = 0.12 g/cm 3 (water/xylene), g = 981.55 cm/s 2 , η = 0.01 g/(cm · s). Thus, the time for one particle to pass a distance equal to its diameter is rather short-of the order of 1 s. Hence, just after a homogeneous dispersion is loaded in a vessel the lowest layer (Fig.…”

“…The boundary between the serum and the creaming droplets is very hazy and difficult to monitor visually. This behavior is typical for highly polydisperse emulsions in which part of the droplets would not flocculate: individual drops and small aggregates move independently to the top of the container (3), and the smallest entities do not sediment at all. In contrast, in the second type of creaming there exists a sharp and clear boundary between the concentrated sedimenting emulsion and the serum layer at the base of the sample.…”

“…In Ref. (3) this kind of behavior was attributed to systems with high degree of flocculation, sufficient to produce a space-spanning structure.…”