Personal web page : http://iramis.cea.fr/Pisp/valerie.geertsen/
Laboratory link : http://iramis.cea.fr/nimbe/lions/
More : http://iramis.cea.fr/Pisp/daniel.bonamy/
The PhD proposal focuses on the design of a new class of metamaterials whose originality lies in both architecture and chemical formulation. These metamaterials take the shape of microarrays. They are therefore much lighter than solid materials. Their architecture is both random and hierarchical (bone structure inspired) to give them sufficient isotropic mechanical response and rupture resistance to consider their use as structural material. The architecture is defined and optimized by calculation within the framework of another thesis [SL-DRF-20-0591, proposed in the NUMERICS program] at the SPHYNX laboratory.
The innovative chemistry of this PhD study wants to give these new metamaterials typical nano-composites properties. This involves improving mechanical, thermal, neutron or fire resistance properties adding substantial quantities of boron-based nanoparticles. Foreseen applications are nuclear installation dismantling or waste transport. The study will focus on spherical B4C nanoparticles whose hardness and high boron content induces important neutrophage properties. The meta materials will be printed by stereolithography in the LIONS laboratory in close collaboration with the SPHYNX laboratory.
More precisely, the study will consist in grafting monomers on nanoparticle surface to optimize their dispersion in the polymer resin. It will also focus on the relationship between nanoparticle (composition, size, shape, content) and printed materials properties (mechanical, thermal, resistance to radiation). These new materials will be analyzed both in their massive and structured form. The PhD student will benefit from the LIONS laboratory expertise in nanoparticles synthesis and grafting, 3D printing and analytical techniques (SAXS, TEM access, ICPMS ...) and radiolysis study facilities. The (visco) elastic behavior, the crushing resistance and the rupture response will be characterized at the SPHYNX laboratory.
The student will also benefit from the interdisciplinary ecosystem created at LIONS and SPHYNX laboratories around the design of these new materials. He/she will learn from the presence of other doctoral students and trainees. This very interdisciplinary work (3D printing, photo-polymerization, nanoparticles, analysis, radiolysis, metallization ...) implies a taste for teamwork as well as an important scientific curiosity and an open mind. The highly instrumental aspect of the project requires also a taste for laboratory work and instrumentation. A polymer chemistry skill will be highly appreciated.