A Sucrose Fatty Acid Ester-mixed Emulsifier as Stabilizer of Emulsion Systems

In the present study, the mesomorphic phase and internal structure of sucrose fatty acid ester (S1670) with cetyl alcohol mixed in different proportions was studied and assessed, within common emulsion system of cosmetics and pharmaceuticals. To characterize the system’s colloidal structure the following physicochemical techniques were used: polarization microscopy, small- and wide-angle X-ray scattering (SAXS and WAXS), differential scanning calorimetry (DSC), continual and oscillatory rheology and cryogenic scanning electron microscopy (cryo-SEM). Ultimately, it was well established that there was a predominant and stable α-crystalline gel structure, formed with sucrose fatty acid ester (S1670) and cetyl alcohol, in the pseudo quarter-phase system (including squalane and aqua). In addition, the optimum ratio for α-crystalline gel formation was found to be around 61.50:38.50 (S1670 to Cetyl alcohol). Moreover, as it deviates from the critical point within a controllable range, although identical α-gel (α-form hydrated crystal) continues to exist, yet the strength and proportion in whole sample decrease with the expansion of deviation. The decent stability (which was derived from the dismatch between the lipophilic chains and the intensive hydration of -OH from S1670) and the agreeable rheological properties of the above α-gel suggest wide application in cosmetics and pharmacy in the future.