Séminaire Exceptionnel
"Matière et Systèmes Complexes"


Jeudi 24 janvier 2008 à 11h30
Bâtiment Condorcet, 6ème étage, salle 646 A.

Jean-Christophe Castaing
(Complex Fluid Lab, Rhodia-CNRS)

Metastable assembly of soft matter : how to build a large variety of properties with a limited set of ingredients

In this seminar, I will present shortly the activities of the Complex Fluids Lab, a joint lab between CNRS and industry (Rhodia) located in Bristol (Pennsylvania) and those that we will develop in partnership with the University of Pennsylvania
(UPenn MRSEC) in the framework of an UMI (Unite Mixte Internationale).

Our project is organized around the problem of "metastable assembly of soft matter". We want to show that rather than spreading in the marketplace a multitude of new products, it will be possible to manufacture a small number of well
analyzed and well controlled colloidal/nano-scale building-blocks that allow for several properties due to their versatility. Metastable assembly is a simple way to get different structures (and therefore properties) by the sole variation
of the
preparation procedure and by keeping the ingredients of a mixture constant.

I will focus mainly on 3 studies (representative of our 3 main competencies : surface modification, rheology of complex fluids and porous media) :

   * the surface modification  by adsorption of complexes of nanoparticles and co-polymers of opposite charge
   * the rheology of multilamellar vesicles
   * the  flows in biphasic porous media : sand and hydrogels

The discussion will be focused on the ways to quantify the versatility of the systems and to classify them in order to define groups that have a consistent behavior.