Anisotropic effects on the rheology of foams containing fibers

Proposition de stage

Laboratoire Sciences et Ingénierie de la Matière Molle, (SIMM)

Adresse : ESPCI, 10 Rue Vauquelin 75005 Paris

Directeur du laboratoire : Jean-Baptiste d’Espinose

Responsables du projet : Emilie VERNEUIL, Anniina SALONEN, Antoine CHATEAUMINOIS

Contact :

Internship with possibility for extension as a fully-funded PhD (CIFRE)

Emerging efforts at reducing water consumption in water-based industrial processes have led to an increased use of foams as a carrier in replacement of plain water in which particles or drops are dispersed. Yet, this use of foams, which consists in dispersion of bubbles in a liquid stabilized with surfactants, requires to revisit their behavior under flow when they contain particles or drops. In this framework, the case of fibers being dispersed in foams is of particular interest because strong anisotropic effects are expected under flow. Indeed, viscous shear is likely to orient the fibers in the flow direction, leading to anisotropic effects. In this internship, we aim at measuring the structural and rheological response of foams containing fibers under shear. To do so, several experimental configurations will be studied and compared. (i) Classical rheology measurement between plates or coaxial cylinders. (ii) Flows in millifluidics. In both cases, we will couple the rheological measurement with direct visualization. Several physical-chemical parameters will be used to gain insights into the behavior of the system : the fiber and gas volume fractions, the amount of surfactant, the viscosity of the continuous phase, the fiber length.

Preliminary experiment : Drainage of a foam containing 1 cm-long fibers with time : the system evolves from a wet foam containing fibers to a network of fibers becoming progressively drier

We are looking for a Master 2 student in materials science, physical-chemistry or physics with an interest in soft matter physics. A PhD position funded by a CIFRE will be available following the internship, for candidates demonstrating strong motivation and research potential.

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