Determination of a coalescence parameter related to the stability of emulsions with polymeric surfactants

✍ Scribed by Evelyne Nakache; Pierre-Yves Longaive; Sébastien Aiello

• Book ID: 103967084
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 510 KB
• Volume: 96
• Category: Article
• ISSN: 0927-7757
• DOI: 10.1016/0927-7757(94)03053-3

✦ Synopsis

The coalescence of single oil droplets at an oil/water interface is studied in relation to emulsion stability. The ternary system used is water/oil/surfactant. The polymeric surfactants are insoluble in the oil phase.

The model of S.K. Chakarova, M. Dupeyrat, E. Nakache, C.D. Dushkin and I.B. Ivanov, (J. Surf. Sci. Technol. 6 (1990) 201 ), which assumes that the drainage depends oll the viscosity of the continuous phase, is used to predict the coalescence time related to the stability of the emulsion. A parameter p, which represents the competition between the effects of the capillary and viscous forces in the system, is deduced.

From a comparison of p with the stability time of an emulsion prepared independently by stirring oil with aqueous phase, a threshold value of p appears which corresponds to the stability of the emulsion.

The parameter p is an intrinsic parameter relating to the constitution of the phases, comparable from one system to another, provided that density and size effects are taken into account and that the experiments are performed under reproducible conditions: the cell phases and the emulsions must be prepared under the same conditions.