Flow anisotropy and flow reversibility of concentrated colloidal suspensions
| Quand ? |
Le 17/05/2022, de 11:00 à 12:05 |
|---|---|
| Où ? | Salle des thèses |
| Participants |
Pascal Hébraud |
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We will present an experimental study of the flow of concentrated suspensions, with an emphasis on the anisotropy of their structure. We consider bidisperse suspensions of microgel particles that, when concentrated enough, exhibit a glassy phase.
In the first part, a light scattering setup under shear will be used to probe the evolution of the structure factor of the suspensions over distances close to the nearest neighbors center-to-center distance, along different directions relative to the flow.
In the second part, a rheological study of the flow of these suspensions in the plastic regime is performed. We show that they exhibit a weakening of their apparent elastic modulus when the flow is reversed, analogous to the Bauschinger effect known in polycrystalline systems. The anisotropy of the structure of the suspension is then computed with molecular dynamics simulations from which this effect is related to the anisotropy of the particles at flow reversal.