Calculation of optimum emulsifier mixtures for phase inversion emulsification*.

Area of Science:

• Colloid and Surface Science
• Cosmetic Science
• Emulsion Technology

Background:

• Phase inversion emulsification is a key technique for producing stable oil-in-water (O/W) emulsions.
• Nonionic emulsifiers are commonly used for O/W emulsion stabilization.
• Understanding phase behavior is critical for optimizing emulsion properties.

Purpose of the Study:

• To introduce and demonstrate the Calculation of Phase Inversion in Concentrates (CAPICO) method.
• To determine emulsifier and oil mixing ratios for a target phase inversion temperature (PIT).
• To investigate the influence of silicone oils on PIT and emulsion stability.

Main Methods:

• Utilized equivalent alkane carbon numbers (EACN) for phase inversion calculations.
• Employed the CAPICO method to predict phase inversion conditions.
• Characterized emulsions using particle sizing and ultrasonic velocity measurements.
• Investigated emulsion phase behavior using temperature/water content graphs.

Main Results:

• The CAPICO method successfully predicted emulsifier and oil ratios for a cosmetic O/W lotion.
• Silicone oils were found to influence the phase inversion temperature (PIT).
• Optimal emulsification was achieved by passing through microemulsion or lamellar phases during PIT emulsification.
• A stable, fine-disperse O/W emulsion was prepared using a two-step hot-cold process.

Conclusions:

• Phase inversion emulsification provides a convenient route to stable O/W emulsions.
• The CAPICO method is a valuable tool for formulating emulsions with controlled phase behavior.
• The developed two-step process is time and energy-efficient for producing high-quality emulsions.