A Study of the Emulsified Microemulsion by SAXS, Cryo‐TEM, SD‐NMR, and Electrical Conductivity

A water‐in‐oil microemulsion was further dispersed in an aqueous phase containing Pluronic F127 as a steric stabilizer, to form a specific type of double emulsion termed emulsified microemulsion (EME). The inner microemulsion phase was made from glycerol‐monooleate (GMO), R(+)‐limonene, ethanol and glycerol. SAXS (small x‐ray scattering), PGSE‐NMR (pulse gradient spin echo‐NMR), electrical conductivity, and cryo‐TEM (cryogenic‐transmission electron microscopy) imaging techniques were used to confirm the existence of inner W/O nano‐droplets after second emulsification step and upon EME aging. Spherical globules of EME without long‐range internal order were observed by the SAXS measurements and the cryo‐TEM images. The average globule size of about 200–300 nm remained intact for at least 6 months.

Keywords:

• Cryo‐TEM
• L₂‐phase
• microemulsion
• emulsified microemulsion
• glycerol monooleate
• electrical conductivity
• SD‐NMR
• SAXS

Acknowledgments

Some of the results presented in this article appear in the thesis of R. L. in partial fulfillment of the requirements for the degree of Doctor in Applied Chemistry, The Hebrew University of Jerusalem, Israel.

The cryo‐TEM experiments were performed at the Cryo‐TEM Hannah and George Krumholz Laboratory for Advanced Microscopy at the Technion. DD acknowledges the support of the Israel Academy of Sciences and Humanities (Grant No. 9059/03).