Self-assembly in escin-nonionic surfactant mixtures: From micelles to vesicles

Area of Science:

• Colloid and Surface Science
• Materials Science
• Biochemistry

Background:

• Saponins are plant-derived surfactants with applications in food, pharmaceuticals, and cosmetics.
• Their potential in formulations is linked to their miscibility with synthetic surfactants.
• Investigating mixed saponin-surfactant self-assembly is crucial due to saponins' unique structures.

Purpose of the Study:

• To investigate the self-assembly structures of escin (a saponin) mixed with nonionic surfactants.
• To understand how varying escin/surfactant ratios and surfactant ethylene oxide chain length influence aggregate structures.

Main Methods:

• Small-angle neutron scattering (SANS) was employed.
• Escin was mixed with nonionic surfactants C12E3 to C12E12.

Main Results:

• Complex structural evolution observed with changes in composition and ethylene oxide chain length.
• Structures ranged from elongated micelles (escin) to spherical micelles (nonionic surfactant).
• Intermediate compositions showed predominantly planar mixed phases, including lamellar, bilamellar, and multilamellar vesicles, and nanovesicles.

Conclusions:

• The study elucidates the intricate self-assembly of saponin-synthetic surfactant mixtures.
• Findings indicate the formation of diverse aggregate structures dependent on composition and surfactant properties.
• This research provides insights for designing novel surfactant formulations utilizing renewable saponins.