Kinetics of Crystallization in Polydisperse Emulsions

Area of Science:

• Physical Chemistry
• Materials Science
• Colloid Science

Background:

• Understanding crystallization kinetics in polydisperse emulsions is crucial for controlling material properties.
• Emulsion droplet crystallization is influenced by factors like droplet size distribution and nucleation site.

Purpose of the Study:

• To analyze the isothermal crystallization kinetics of droplets within polydisperse emulsions.
• To derive expressions for crystallization time and ultrasound velocity changes.
• To investigate the effect of emulsion polydispersity on crystallization rates.

Main Methods:

• Mathematical modeling of isothermal crystallization kinetics.
• Derivation of time-dependent expressions for crystallized droplet numbers and volumes.
• Analysis of ultrasound velocity changes during crystallization.
• Comparison of theoretical predictions with experimental data for palm oil and n-hexadecane emulsions.

Main Results:

• Expressions derived for time-dependent crystallization considering volume or surface nucleation.
• Half-crystallization time is inversely related to emulsion polydispersity.
• Ultrasound velocity change formulas obtained for polydisperse emulsions during crystallization.
• Excellent agreement between theoretical models and experimental data.

Conclusions:

• Emulsion polydispersity significantly influences crystallization kinetics, leading to faster crystallization.
• The derived models accurately predict crystallization behavior and ultrasound velocity changes.
• Findings are applicable to devitrification and polymorphic transformations of dispersed solids.