Deciphering the mechanical and vibrational properties of colloidal gels from structural and elastic heterogeneities
| When |
May 28, 2024
from 11:00 to 12:00 |
|---|---|
| Where | Salle des thèses |
| Contact Name | Thibaut Divoux |
| Attendees |
Mehdi Bouzid |
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Adhesive colloidal particles dispersed in a fluid can self-assemble into a rigid percolating network called a gel. They are ubiquitous in nature and in many industrial processes ranging from batteries and foodstuffs to pharmaceutical products. Therefore, understanding and predicting their mechanical response is crucial. In this talk, I will show that the emergence of elasticity is controlled by a rigidity percolation transition, from which we can extract a characteristic correlation length scale that probes the size of the elastic and structural heterogeneities, which diverge at the critical point. We demonstrate that independently of the nature of the particle-particle interactions, their concentration, as well as the path through which non-ergodicity is attained (the preparation protocol), the elastic modulii and the vibrational properties of these soft solids can be predicted by a mean-field description in which bending modes of fractal clusters of about the size of the correlation length dominate under small mechanical deformation.