Formation and Stability of Nano-Emulsions Prepared Using the Phase Inversion Temperature Method

TLDR

O/W nano‑emulsions in water/C12E4/oil systems are formed using the phase‑inversion‑temperature method. Emulsification was performed at the HLB temperature and rapidly cooled to 25 °C, and droplet size (via DLS) and stability (size change over time) were evaluated as functions of surfactant concentration and oil solubility. Nano‑emulsion breakdown was attributed to Ostwald ripening, and higher surfactant concentration and oil solubility increased instability.

Abstract

Formation of O/W nano-emulsions has been studied in water/C̄12Ē4/oil systems by the phase inversion temperature emulsification method. Emulsification was carried out at the corresponding HLB (hydrophilic−lipophilic balance) temperature, and then the emulsions were cooled fast to 25 °C. The influence of surfactant concentration and oil solubility on HLB temperature, nano-emulsion droplet size, and stability has also been studied. Droplet size was determined by dynamic light scattering, and nano-emulsion stability was assessed, measuring the variation of droplet size as a function of time. The results obtained showed that the breakdown process of nano-emulsions studied could be attributed to Ostwald ripening. An increase of nano-emulsion instability with the increase in surfactant concentration and oil solubility was also found.