Paris-Sud / CSC program 2015 PhD project proposal form Please convert this file to PDF format before uploading it to http://www.u-psud.fr/csc/ Discipline Physics & Engineering Sciences Doctoral School 534 - Modelling and Instrumentation in Physics, Energy, Geoscience and Environment Thesis subject title Role of the drying rate onto the nano-structure of films formed by the evaporation of colloidal suspensions Laboratory name Laboratory web site ! ! ! ! ! ! ! FAST http://www.fast.u-psud.fr PhD supervisor (contact person) Name LAZARUS Véronique Position Maitre de conférences Email [email protected] Phone number 01 69 15 80 39 Thesis proposal (max 1500 words) ! ! ! Drying a colloidal suspension yields the formation of a thin solid film with more or less porosity, optical transparency, and resistance to fracture. This process is central in many industrial applications : sol-gel processes for glasses, ceramics, nanocomposites or organo-mineral hybrid in chemistry & pharmacology painting and protective coating in glass and aerospace industries, highperformance plaster and concrete in civil engineering… As consequences, to understand and subsequently to predict and control the mechanisms driving the fracture resistance, porosity, stiffness and optical properties of the so-obtained film Paris-Sud / CSC program 2015 PhD project proposal form represent a major challenge. These macroscopic properties are the signature of nanoscopic properties : organisation and nature of the chemical bonds within the porous media. ! ! ! The objective is to study, on a model colloidal suspension (Nanoscale silica beads in suspension), the influence of the drying rate, film thickness and bead dimension and polydispersity on the above macroscopic properties. Indentation tests, acoustic measurements, mercury porosimetry, and optical index measurements will be performed at macroscopic scales. At the nanoscale, we will make use of a new generation AFM dedicated to real-time imaging of nanomechanical properties (elastic modulii, local adhesion…) down to scales of the nanometers. ! Collaborations: G. Gauthier (FAST), C. Rountree (CEA), D. Bonamy (CEA) Publications of the laboratory in the field (max 5) 1. Structural anisotropy of directionally 2. 3. 4. 5. ! dried colloids F. Boulogne, L. Pauchard, F. Giorgiutti-Dauphiné, R. Botet, R. Schweins, M. Sztucki, J. Li, B. Cabane and L. Goehring, accepté Europhys. Lett. (2014) Crack patterns obtained by unidirectional drying of a colloidal suspension in a capillary tube: experiments and numerical simulations using a two-dimensional variational approach. Maurini, C. and Bourdin, B. and Gauthier, G. and Lazarus, V. International Journal of Fracture 184, 75--91(2013). Mechanical Stresses Induced by Evaporation in Consolidated Colloidal Suspensions of Hard Particles. Poroelasticity Theory Versus Experiments. Chekchaki, M., , Lazarus, V., Transport in Porous Media 100, 143--157 (2013). From craquelures to spiral crack patterns: influence of layer thickness on the crack patterns induced by desiccation. Lazarus, V., Pauchard, L., Soft Matter 7 , 2552-2559 (2011). Shrinkage star-shaped cracks: Explaining the transition from 90 degrees to 120 degrees. Gauthier, G., Lazarus, V., Pauchard, L., EPL 89, 26002 (2010). Specific requirements to apply, if any …………