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Reference : UMR7057-CARPHI-003
Workplace : PARIS 13
Date of publication : Wednesday, May 06, 2020
Scientific Responsible name : Elisabeth GUAZZELLI
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2020
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Suspensions, which are consisting of mixtures of particles dispersed in a liquid, are ubiquitous in natural phenomena (transport of sediments in rivers and oceans, landslides, avalanches, pyroclastic flows) and in industrial processes (food industry and cosmetics, civil engineering and petroleum industry, paper and composite industries). If the rheology of suspensions is well understood since the seminal work of Einstein in the dilute or semi-dilute regimes where the hydrodynamic interactions between the particles predominate, it is far from being completely elucidated in the concentrated regime. Indeed, at these volume fractions, the contacts between particles become dominant leading to a divergence of the viscosity at a jamming transition where the flow stops.
In the regime of large concentration, the major problem is to link the mechanics at the grain scale to the macroscopic rheological properties. Theoretical and numerical studies have recently highlighted the role of friction between particles and more broadly the role of the interactions between these particles (electrostatic, steric for example). However, it is difficult experimentally to explore suspensions over the whole range, from particles having purely lubricated interactions (without frictional contact) to particles having solid contact with friction. The present project proposes to move in this direction by manufacturing chemically functionalized particles. This functionalization aims at affecting the interactions between the particles and between the particles and the suspending fluid and could make possible the examination of the transition between suspensions where the particles have only lubricated interactions (without friction) and where there is frictional contact between the grains (with friction). The objective of the thesis is therefore the development of particles of controlled functionalization and the study of their rheological studies.
Work Contex :
The thesis will take place between the Sciences and Engineering of Soft Matter (SIMM) laboratory at ESPCI and the Matter and Complex Systems (MSC) laboratory of Paris University.
Candidate profile :
The student will have an experimental profile in material chemistry, with knowledge in chemistry and physicochemistry of soft matter, and will need to be curious and imaginative.
Nicolas SANSON (SIMM, ESPCI-SU-CNRS,
Matthieu ROCHE (MSC, CNRS - Paris University - Site Condorcet)
Elisabeth GUAZZELLI (MSC, CNRS - Paris University - Site Condorcet)
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