Effect of glycerol addition on the internal structure and thermal stability of hexosomes prepared from phytantriol

Hierarchical organization is a characteristic feature of soft and bio-soft matter. Understanding the physical properties of such structures is essential for the formulation of new functional materials. Internally self-assembled dispersions comprise two levels of hierarchy. An equilibrium nanostructured material is confined to a kinetically stabilized submicrometer particle. In the present contribution we focus on confined inverse hexagonal phases; i.e., hexosomes. The confined structure is built up by n-tetradecane and the hydrophobic surfactant phytantriol, while the particles are stabilized by the triblock copolymer Pluronic F127. The effect of glycerol on the confined structure was determined by using small-angle X-ray scattering. Phase transitions inside the particles from inverse hexagonal to water-in-oil microemulsion at constant temperature could be observed, an effect that is similar to that produced by raising the temperature or adding oil. Dynamic light scattering performed before and after freezing revealed that as little as 10 wt% glycerol in the continuous water phase is sufficient to stabilize the dispersion.