Effect of surfactant phase behavior on emulsification.

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Physical Chemistry

Background:

• Amphiphilic block copolymers, such as polyoxyethylene-polyoxypropylene-polyoxyethylene (POE-POP-POE) Pluronics, are crucial for stabilizing emulsions.
• The equilibrium phase behavior and structure of these amphiphiles significantly influence emulsification processes and final emulsion properties.
• Understanding these relationships is key to developing advanced emulsion formulations.

Purpose of the Study:

• To investigate the impact of Pluronic amphiphiles' phase behavior and structure on emulsion formation and characteristics.
• To explore ternary systems of specific Pluronics (F38, L64, P84, P104, L121) with water and p-xylene.
• To correlate emulsification pathways and resulting structures with emulsion homogeneity and droplet size.

Main Methods:

• Preparation of emulsions with identical final compositions using varied emulsification routes.
• Characterization of lyotropic liquid crystalline (LLC) phases using small-angle X-ray scattering (SAXS).
• Evaluation of emulsion properties, focusing on homogeneity and droplet size distribution.

Main Results:

• Emulsions prepared via pathways involving lamellar gel structures or traversing the lamellar LLC phase exhibited finer and more homogeneous characteristics.
• The lamellar structure demonstrated favorable properties, including high oil solubilization, facile water dispersibility, low interfacial tension, and low viscosity.
• Specific Pluronic types and their phase transitions influenced the observed emulsion properties.

Conclusions:

• The formation and traversal of lamellar LLC phases during emulsification are critical for achieving high-quality emulsions.
• Lamellar structures offer a unique combination of properties beneficial for emulsion stabilization.
• These findings provide valuable insights for the rational design of emulsions across diverse industrial applications, including cosmetics, pharmaceuticals, and materials synthesis.