Engineering Mechanics of Soft Interfaces
We study two things:
1. How things break
2. How dry things become wet and how wet things become dry
Our research in detail:
The mechanical response of soft materials is dominated by interfaces, from foams to liquid droplets to hydrogels. Despite incredible progress over the past decades, significant important questions concerning the mechanical response of interfaces remain open. Specifically, these open questions are centered upon the mechanical response of interfaces with propagating singularities. In propagating singularities, the far-field, global forcing drives a small-scale, geometrically sharp feature to move, such as occurs at the edge of an advancing contact line, or at the tip of a propagating crack. These seemingly disparate phenomena are connected in the mathematical framework of propagating singularities; however, applying existing solutions to real materials is challenging. As the material is stressed to its limits across scales from the global loading to the sharp geometric feature, its response can become non-linear. Both liquid contact lines and cracks push the material beyond its linear response, severely limiting the applicability of the solutions obtained in the existing theoretical frameworks.
In our work, we aim to address the significant challenges centered on the mechanical response of soft interfaces experimentally. Our effort is driven by expertise in applying direct observation and advanced imaging techniques to gather key kinematic data. These kinematic data allow us to observe symmetry breaking, identify key length scales that resolve the diverging stresses at propagating singularities, and determine how surface stresses alter the bulk response of soft materials.
La nuit des Idees: Institut Francais Tunis
Wassim Dhaouadi speaks about Bretherton's buoyant bubble at the Institut Francais Tunis – Nuit des Idees 2020