Liquid Crystal Cubic Phases Constructed from Sophorolipids Micelles

Area of Science:

• Biochemistry
• Materials Science
• Colloid Science

Background:

• Biosurfactants are sustainable alternatives to synthetic surfactants.
• Sophorolipids (SL) are glycolipid biosurfactants with diverse applications.
• Understanding their aqueous phase behavior is crucial for application development.

Purpose of the Study:

• To investigate the aqueous phase behavior of sophorolipids (SL).
• To construct the binary phase diagram of the SL/H2O system.
• To characterize the resulting liquid crystalline phases and their properties.

Main Methods:

• Polarized microscopy
• Small-angle X-ray diffraction (SAXS)
• Nuclear magnetic deuterium spectroscopy (2H NMR)
• Transmission electron microscopy (TEM)
• Freeze-etched transmission electron microscopy (FF-TEM)
• Dynamic light scattering (DLS)
• Rheological measurements

Main Results:

• A micellar phase exists at low SL concentrations (<50 wt %).
• A liquid crystalline cubic phase, composed of ordered spherical micelles, forms at higher concentrations (up to 70 wt %).
• This micellar cubic phase exhibits high viscosity, viscoelasticity, and temperature-dependent reversibility.

Conclusions:

• Sophorolipids form a unique micellar cubic liquid crystalline phase in water.
• The phase behavior and rheological properties indicate potential for various applications.
• The observed temperature reversibility is advantageous for practical use.