Influence of the stabilizer concentration on the internal liquid crystalline order and the size of oil-loaded monolinolein-based dispersions.

The internal phase of monolinolein-based dispersions loaded with tetradecane or (R)-(+)-limonene was investigated as a function of the stabilizer content by small-angle X-ray scattering. Phase transitions at the colloidal scale were found in some of nanostructured aqueous dispersions by increasing the stabilizer content. For particles containing a bicontinuous cubic phase, a large increase of the stabilizer concentration promoted a liquid crystalline phase transition from the Pn3m to the Im3m cubic symmetry. The coexistence of both phases is observed in an intermediate stabilizer concentration range. For particles with an internal micellar cubic Fd3m symmetry, the internal structure changes in the isotropic fluid L(2) phase. In case of particles with an internal hexagonal phase (H(2) symmetry), the increasing amount of stabilizer did not alter the lattice parameter but decreased the size of the nanostructured domain. Moreover, we showed for hexagonal and emulsified micellar phase particles that the increase of the stabilizer content induced a strong decrease of the mean hydrodynamic size of the particles, allowing producing nanostructured lipid-based liquid crystalline particles down to a radius of 70 nm at the same energy input.