Institut Charles Sadron Event

In a first example I will show how we can assemble polymers using hydrogen bonding interactions to obtain highly stable oil in water emulsions. A rigid interfacial layer can be obtained either by assembling the polymers layer by layer at the oil/water interface or in a one step process, using oil and water soluble polymers in each liquid phase, which assemble spontaneously at the interface. I will show how the type of interaction involved between the interfaces controls the mechanical properties and stability of the drops. In the second example, we dripped alginate droplets into a calcium bath to obtain gelled alginate capsules. As they hit the calcium bath the alginate droplets spread on the bath and then relax toward a more spherical shape as they fall into the bath. Using a high speed camera we investigated the coupling between the gelling reaction and the dynamics of the droplets. We show that the syneresis mechanism, leading to the expulsion of water from the hydrogel beads controls the relaxation process and final shape of the capsules.