Intertwining Roles of the Disperse Phase Properties during Emulsification

Area of Science:

• Colloid and Surface Science
• Materials Science
• Chemical Engineering

Background:

• Emulsification is crucial for various industries, but controlling droplet size remains challenging.
• Understanding the interplay of physical parameters like viscosity, interfacial tension, and density is key to optimizing emulsion formation.
• Previous studies have shown complex relationships between these parameters and droplet characteristics.

Purpose of the Study:

• To investigate the combined effects of viscosity ratio, interfacial tension, and disperse phase density on droplet formation during emulsification.
• To analyze the influence of these parameters on droplet size evolution over time.
• To explore the impact of surfactant presence and addition timing on emulsion stability and formation.

Main Methods:

• Emulsification of oil/water systems using ultrasonication across a wide range of viscosity ratios (1-600).
• Inclusion of experiments with and without surfactant to differentiate their effects.
• Dynamic light scattering measurements to track the time evolution of average droplet size.

Main Results:

• Results partially replicate the U-type trend for viscosity ratios up to 200 with surfactant.
• Beyond a viscosity ratio of 200, droplet size decreases with increasing viscosity ratio.
• Surfactant-free systems show minimal change in droplet size with increasing viscosity; interfacial tension and internal properties dictate droplet rupture dynamics.

Conclusions:

• The study elucidates the complex interplay between viscosity ratio, interfacial tension, and density in droplet formation.
• A critical finding is that delayed surfactant addition can yield stable emulsions comparable to early addition, offering energy and time savings.
• These insights are valuable for optimizing emulsification processes in industrial applications.