Comparative study of the stabilizing behavior of organoclays in Pickering emulsion.

AbstractPickering Emulsions are commonly applied in the pharmaceutical, food, and chemical industries. The use of natural particles as stabilizers provides access to surfactant-free dispersions with reduced toxicity and environmental impact. This work investigates the use of three commercial organoclays (C15A, C10A, and C30B) and hydrophilic sodium montmorillonite (Mt) as stabilizers for Pickering emulsions. Emulsion stability was evaluated through macroscopic and microscopic morphological observations and the emulsion microstructure was characterized by optical microscopy and DLS measurements to assess creaming and coalescence. The influence of different experimental parameters on emulsion stability was evaluated, including organoclay content, emulsification time, emulsification speed, and oil–water ratio. The results showed that emulsions based on C15A exhibit better stability against coalescence as compared to emulsions prepared with the other clays. This was attributed to the wettability of the particles and solution viscosity. Droplet size decreased as emulsification time and stabilizer content increased and reached a minimum value at 1 wt.% of C15A and for emulsification time of 5 min and oil–water ratio O/W (v/v: 50/50). The experimental parameters also impacted emulsion viscosity, increasing it for high clay content and as the stirring speed and emulsification time increased. The results of the heat and cold resistance stability tests indicated that 25 °C represents the optimal storage temperature for the prepared emulsions. [ABSTRACT FROM AUTHOR]