Paper Number
IR18
Session
Interfacial Rheology
Title
Elastoviscoplastic behaviour of model particle-laden interfaces
Presentation Date and Time
October 11, 2022 (Tuesday) 9:50
Track / Room
Track 5 / Sheraton 2
Authors
- Alicke, Alexandra (ETH Zürich, Department of Materials)
- Stricker, Laura (ETH Zürich, Department of Materials)
- Tervoort, Theo A. (ETH Zurich, Department of Materials)
- Vermant, Jan (ETH Zürich, Materials)
Author and Affiliation Lines
Alexandra Alicke, Laura Stricker, Theo A. Tervoort and Jan Vermant
Department of Materials, ETH Zurich, Zurich, ZH 8093, Switzerland
Speaker / Presenter
Alicke, Alexandra
Keywords
experimental methods; colloids; gels; interfacial rheology; microscopy; suspensions
Text of Abstract
Colloidal particles are widely employed to provide Pickering stability to high interface systems. Their colloidal nature makes them prone to irreversibly adsorb at interfaces, and the flexibility to tune interactions makes them ideal candidates as model systems to understand the behavior of more complex interfaces. Typically, they are used to fully cover the surface of bubbles and droplets, though it has been recently shown [1] that the existence of an interfacial yield stress at sub-monolayer coverages suffices to resist bubble dissolution (and the main driving force for Ostwald-ripening). Analogously to bulk materials, the viscoplastic nature can be achieved by different material design routes. However, differently than their 3D counterparts, these 2D materials have the advantage of being compressible, which means that we can experimentally interrogate the full tensorial nature of yielding for constitutive modelling. Here, we experimentally interrogate the shear and compressional/dilatational rheological properties of particle-laden interfaces of both i) flocculated particle interfaces that behave as 2D gels and ii) dense particle interfaces close to monolayer coverage. By using custom-built interfacial rheology set ups, which enable clean kinematic conditions, combined with microscopic observations of the 2D suspension microstructure, we investigated the transition from linear to nonlinear behavior. In this way, we are able to relate the rheological properties to underlying changes in microstructure, and identify the limits of elastic deformation, the occurrence of plastic events, and the different responses to shear or compression. These results are not only relevant to the field of interfacial rheology, but can also provide insights into the yielding behavior of bulk materials.
[1] P. Beltramo, M. Gupta, A. Alicke, Irma Liascukiene, Deniz Z. Gunes, Charles N. Baroud, and Jan Vermant, PNAS, 2017 114(39), 10373-10378