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Shear-induced phase transitions in sucrose ester surfactant
Véronique M Sadtler1, Michèle Guely, Philippe Marchal
1Centre de Génie Chimique des Milieux Rhéologiquement Complexes, GEMICO-Groupe ENSIC, 1 rue Grandville, BP 451, F-54001 Cedex, Nancy, France. veronique.sadtler@ensic.inpl-nancy.fr
Journal of Colloid and Interface Science
|December 31, 2003
Summary
This study reveals how sucrose stearate blends form lamellar liquid crystalline phases in water. A small amount of distearate is key for forming stable vesicles at low concentrations.
Area of Science:
- Materials Science
- Physical Chemistry
- Colloid Science
Background:
- Sucrose stearate blends are widely used emulsifiers.
- Understanding their phase behavior in water is crucial for formulation development.
- Lyotropic mesophases are important in various applications, including cosmetics and food products.
Purpose of the Study:
- To investigate the phase behavior of a commercial sucrose stearate blend in water.
- To establish a partial phase diagram and characterize the mesophases formed.
- To explore the conditions leading to vesicle formation.
Main Methods:
- Differential scanning calorimetry (DSC)
- Polarization microscopy
- Electron microscopy (including freeze-fracture)
- Rotational rheometry
Main Results:
- A lamellar lyotropic mesophase was identified.
- A lamellar gel-lamellar liquid crystalline phase transition was observed.
- A shear-induced transition to an onion phase occurred above 43°C.
- Stable vesicles formed at low surfactant concentrations, attributed to distearate presence.
Conclusions:
- Sucrose stearate blends form lamellar liquid crystalline phases in water.
- Vesicle formation at low concentrations is facilitated by the distearate component.
- The study provides insights into the self-assembly behavior of sugar ester surfactants.