François LEQUEUX – Foamability and bubble lifetime of oil mixtures

Foamability and bubble lifetime of oil mixtures

Classical aqueous foams are stabilized by surfactants. The role of surfactants is to generate repulsive interactions between thin films interfaces and thus to stabilize foams. On the contrary, for oil mixtures, thin films undergo only attractive Van der Waal interaction, and thus cannot be stable. However, oil mixtures (like for instance decane /toluene mixtures) can form foams that last for a tens of seconds, a value large enough to be an annoyance for many situations (oil extraction, lubricants, food industry). This phenomenon has been observed 50 years ago but not yet understood.

We will explain the origin of the foaming behavior of oil mixtures, and discuss their specific mode of bursting (see image below). Indeed, foam life and death that can be understood quantitatively, due to the simplicity of oil mixtures physico-chemistry.

François LEQUEUX, Sciences et Ingénierie de la Matière Molle, ESPCI/PARIS/France

Francois.lequeux@espci.fr