Cubic-Phase-Based Concentrated Emulsions.

Area of Science:

• Colloid and Surface Science
• Materials Science
• Physical Chemistry

Background:

• Investigating liquid crystal phases is crucial for understanding surfactant behavior.
• The water-polyoxyethylene dodecyl ether (C(12)EO(25)) system is a model for studying phase transitions.
• Understanding the influence of additives like oils and polyols is key to controlling phase behavior.

Purpose of the Study:

• To investigate the effect of different oils on the formation and stability of discontinuous micellar-type cubic phases in C(12)EO(25) systems.
• To examine the impact of polyols on the thermal stability of these cubic phases.
• To explore the formation of concentrated emulsions based on the cubic phase.

Main Methods:

• Phase study of water-C(12)EO(25)-oil systems.
• Small-angle X-ray scattering (SAXS) for structural analysis.
• Thermal analysis to determine phase stability and melting points.

Main Results:

• Oil addition, especially short-chain hydrocarbons, increases the thermal stability of the cubic phase.
• Heptane addition resulted in a lower melting temperature than decane due to a different liquid crystal phase formation.
• Polyol addition decreased cubic phase thermal stability, with greater destabilization at higher concentrations and deeper polyol penetration.
• Transparent cubic-phase-based concentrated emulsions formed due to minimal refractive index differences between phases.

Conclusions:

• The type and concentration of oil significantly influence the thermal stability and phase behavior of C(12)EO(25) cubic phases.
• Polyols act as destabilizers for these cubic phases, with their effect dependent on molecular structure and concentration.
• Cubic phases can incorporate large amounts of excess oil, forming stable, transparent emulsions with potential applications.