The study of interfaces

• The water/air interfaces are mainly characterised using three Langmuir balances.

One of these is used to take samples using the Blodgett technique and then characterise the structure of the interfaces using atomic force microscopy (AFM). Another is confined in a glove box to control the atmosphere above the interface, for example to study the oxidation mechanisms of different molecules at the interfaces. We also have infrared spectroscopy equipment mounted on a Langmuir balance (IRRAS) to characterise the structure of molecules at the interface.

• The water/oil interfaces are mainly studied using the two drop tensiometers at our disposal, which also enable us to characterise the rheology of the interfaces. Surface shear equipment is also used to measure this parameter. In addition, one of our drop tensiometers is equipped with an external phase exchange device, which enables us to vary the composition of the liquid phase in which the drop is immersed during the experiments.

We are also endeavouring to relate the results obtained at model interfaces to the properties observed in real systems, emulsions and foams. To characterise the interfaces in situ, the BIBS platform provides us with various microscopic techniques for characterising real systems at different scales (confocal microscopy, TEM). We also have access to large instruments (Synchrotron Soleil) to characterise the fine structure of assemblies in solution or at interfaces using neutron or X-ray scattering.