O/W/O Multiple Emulsions via One‐Step Emulsification Process

Abstract

The preparation of O/W/O multiple emulsions by a one‐step emulsification process was studied using an optical microscope equipped with a camera. The O/W/O multiple emulsions could be prepared by the introduction of two surfactants and two polymers. But when one of two polymers or water‐soluble surfactant was not added, W/O emulsions with various size distributions were formed. Tween 20 added in water destabilizes W/O interfacial films formed by Span 80. At a result, the diffusion of 1‐octanol into water droplets occurred more easily. Using a polymer in the continuous phase, the swelling of W/O interfaces was retarded but the use of two polymers in the continuous and discontinuous phases assisted the micelles mixed with oil molecules to diffuse into the core of aqueous droplets and remain. Moreover, the interaction between Tween 20 and PEG promoted coalescence of oil‐swollen micelles in the water droplets. Depending upon the choice of water‐soluble nonionic surfactants and polymers, three types of emulsion droplets were observed. Variation in the shapes of the droplets was due to differences in solubilization power of the surfactants. Also, the O/W/O multiple emulsions were stable for 8 h but most of the emulsions were at least partially broken after 24 h.

Keywords:

• Multiple emulsion
• One‐step emulsification
• Polymers
• Interface
• Stability

Acknowledgment

This research was funded by Center for Ultramicrochemical Process Systems sponsored by KOSEF.