Effect of molecular weight of triglycerides on the formation and rheological behavior of cubic and hexagonal phase based gel emulsions

The effect of triglyceride molecular weight on the formation and rheology of cubic (O/I1) and hexagonal (O/H1) phase based gel emulsions has been studied in water/C12EO8 systems. It was found that the addition of TDG (1,2,3-tridecanoyl glycerol) in the micellar solution leads to the formation of the I1 phase, which can solubilize some added oil. From SAXS data, it is revealed that the interlayer spacing (d) and the length of hydrophobic part (rI) increase with increasing TDG concentration in the I1 phase, whereas the effective cross-sectional area (as) decreases. After the oil solubilization limit, the d value remains nearly constant, indicating the I1+O phase appears. The high viscosity of the I1 phase facilitates the formation of the O/I1 gel emulsion. It has been observed that the formation and stability of the O/I1 and O/H1 gel emulsion is highly dependent on the molecular weight of triglycerides, namely, the high molecular weight triglycerides show better performance (formation and stability) compared to the low molecular weight triglycerides. The rheological behavior of the I1 phase was found to change from viscoelastic to elastic nature with TDG content. The values of the complex viscosity, ∣η*∣ show different trends at different fixed frequencies within the I1 phase, whereas it decrease monotonically in the O/I1 gel emulsions. The increasing values of the ∣η*∣ (at lower frequency) could be due to the neighboring micellar interaction and decreasing values of the ∣η*∣ in the O/I1 gel emulsion could relate to the volume fraction of the I1 phase in the system. It is also figured out that the rheological parameters (elastic modulus, viscous modulus, and ∣η*∣) of the O/I1 the gel emulsion do not depend on the oil nature, whereas the O/H1 gel emulsion shows oil nature dependency.

The effect of triglyceride molecular weight on the formation and stability of liquid crystal (LC) based gel emulsions has been investigated in water/C12EO8/triglyceride systems.Figure optionsDownload as PowerPoint slide