Soft Matter Seminar: Aluminosilicate Materials: from soft gel to solid binder
Arnaud Poulesquen, Researcher-Engineer at CEA, the French Atomic Energy Commission
Thanks to their environmental acceptability and their adaptability over a wide range of applications, alkali solutions of aluminosilicates are increasingly used for their important role as inorganic and water based binders (geopolymer, precursors of zeolites…), notably for the production of mineral based, ecological materials for the building and construction industry. Although such solutions are increasingly used in the industry, there remain outstanding questions regarding the gelation process, that are driven by the composition of the solution, their stabilities and their aging. It is therefore crucial to provide a clear and realistic description of such materials in order to tune and tailor macroscopic properties.
My talk aims to describe two kind of aluminosilicate materials: a solid one named “geopolymer” and a soft one. Geopolymers are synthesized by the activation of aluminosilicate source (metakaolin) in an alkaline silicate solution. This creates a porous network of mesopores and macropores with high mechanical resistance. I will detail the different step of geopolymerization from liquid to solid state. The second part of my talk will concern the characterization of aluminosilicate soft gels that are considered as some precursors of zeolites. The link between macroscopic properties throughout a variety of rheological tests and mesoscopic properties by the use of time resolved Small Angle X-ray Scattering (SAXS) will be describe and detail from the liquid to gelling state. A clear understanding of these inorganic materials from chemical, structural and mechanical point of view will be very useful for many applications in nuclear and civil engineering industries.
Arnaud Poulesquen is Researcher-Engineer at CEA, the French Atomic Energy Commission. His research interests concern the relation between rheological and structural properties in various materials as alkali activated materials (mainly geopolymers under various shape: bulk, emulsions and foams), soft gels and bitumen. The characterization of porous materials and fluid transport properties combining calorimetry and neutrons or X-ray scattering experiments is also a part of his reserch. He graduated in 2001 with a PhD in materials science from the Ecole Nationale Supérieure des Mines de Paris and received his Habilitation degree from the University of Montpellier in 2013. He joined the international joint unit (UMI) Multiscale Science for Energy and Environments as a visiting scientist for working on aluminosilicates materials from modeling and experimental point of view.
Monday, April 15 at 10:00am
Regents Hall, 351
3700 O St. NW