Complex Fluid-Fluid Interfaces

We focus on the role of complex interfaces and the mechanical response that these interfaces brings about. We have developped tools to study the interfacial rheological behaviour and the effects of interfacial rheology on stability.

Novel experimental tools for monolayers and bilayers

In recent years we made some progress in particular for interfaces where rheological stresses, peculiar to the interface, play an important role. For shear rheometry, examples include the Double Wall Ring. Progress in analyzing the flow field in the measurement device has been key, combined with advances in control over surface concentration and microstructural evaluation. For dilation/compressional rheometry, much work has been done on separating changes in the surface tension from the extra rheological stresses using a home-made radial trough. We also use a thin film balance, as “simple complex flows”, such as thin film and drainage flows, offer a first step up in complexity and seem to present a good benchmark problem for testing constitutive equations and the interplay between transport phenomena, interfacial rheology and the changes in state variables. We also pursued new tools which open promising pathways to study bilayer mechanics.

Selected references

Chatzigiannakis, E., Jaensson, N., & Vermant, J. (2021). Thin liquid films: Where hydrodynamics, capillarity, surface stresses and intermolecular forces meet. Current Opinion in Colloid & Interface Science, 53, 101441.
Vutukuri, H. R., Hoore, M., Abaurrea-Velasco, C., van Buren, L., Dutto, A., Auth, T., G.. gommper & Vermant, J. (2020). Active particles induce large shape deformations in giant lipid vesicles. Nature, 586(7827), 52-56.
Renggli, D., Alicke, A., Ewoldt, R. H., & Vermant, J. (2020). Operating windows for oscillatory interfacial shear rheology. Journal of Rheology, 64(1), 141-160.
Chatzigiannakis, E., & Vermant, J. (2020). Breakup of thin liquid films: From stochastic to deterministic. Physical Review Letters, 125(15), 158001.
Jaensson, N., & Vermant, J. (2018). Tensiometry and rheology of complex interfaces. Current opinion in colloid & interface science, 37, 136-150.

Constitutive modelling of interfaces

Within a continuum mechanical description, we work on developping and testing constituive models for interfaces.We started with neo-hookean interfaces, where the additional complexity of an interface being compressible comes into play. `Further work is focusing on plasticity and the molecular/structural basis of all that.

Selected References

Pepicelli, M., Jaensson, N., Tregouët, C., Schroyen, B., Alicke, A., Tervoort, T., .C. Monteux & Vermant, J. (2019). Surface viscoelasticity in model polymer multilayers: From planar interfaces to rising bubbles. Journal of Rheology, 63(5), 815-828.
Pepicelli, M., Verwijlen, T., Tervoort, T. A., & Vermant, J. (2017). Characterization and modelling of Langmuir interfaces with finite elasticity. Soft Matter, 13(35), 5977-5990.
Verwijlen, T., Imperiali, L., & Vermant, J. (2014). Separating viscoelastic and compressibility contributions in pressure-area isotherm measurements. Advances in colloid and interface science, 206, 428-436.

Applications

We look at a broad range of applications w.r.t. the role of particles , the role of proteins or polymers in stabilization. Applications in foaming or defoaming, emulsion stability, lung surfactants and building materials have been or are being considered. Beer foam stability or bread baking have also been adressed.The image shows a falso colour image of thin film of Belgian beer. Also Aerosols and aaerosol stability - related tot he COVID pandemic have been/are being studied as well as vesicles being deformed.

Selected references.

Bayles, A. V., & Vermant, J. (2022). Divide, Conquer, and Stabilize: Engineering Strong Fluid–Fluid Interfaces. Langmuir.
Chatzigiannakis, E., & Vermant, J. (2021). Dynamic stabilisation during the drainage of thin film polymer solutions. Soft Matter, 17(18), 4790-4803.
Chatzigiannakis, E., Veenstra, P., Ten Bosch, D., & Vermant, J. (2020). Mimicking coalescence using a pressure-controlled dynamic thin film balance. Soft Matter, 16(41), 9410-9422.
Dockx, G., Geisel, S., Moore, D. G., Koos, E., Studart, A. R., & Vermant, J. (2018). Designer liquid-liquid interfaces made from transient double emulsions. Nature communications, 9(1), 1-8.
Beltramo, P. J., Gupta, M., Alicke, A., Liascukiene, I., Gunes, D. Z., Baroud, C. N., & Vermant, J. (2017). Arresting dissolution by interfacial rheology design. Proceedings of the National Academy of Sciences, 114(39), 10373-10378.