Séminaire LJC de Laurent Heux

In the framework of the LJC seminars the 22nd of January at 11h Laurent Heux is giving a seminar in the big CBP conference room.

Bioinspired materials obtained by self-assembling properties of elementary bricks : from the primary wall to the iridescence of beetle shells

Laurent Heux, CERMAV-CNRS, BP 53, 38 041 Grenoble Cedex 9

Natural structures exhibit spectacular properties like, for instance, the iridescence of beetle shells, and can therefore be a source of inspiration to design innovative materials. In several situations, those structures are obtained by smart assemblies of crystalline polysaccharides in association with other polymers. In vivo, those systems are designed to ensure support and protection of a great number of organisms like in plant cells and exoskeletons of insects or crustaceans, and are probably the most widespread architectures in the living world.

Starting from elementary bricks, it’s possible to reproduce in vitro at least some of the natural structures. For instance, we have elaborated multilayered assemblies mimicking the primary wall , taking advantage of the specific interaction between cellulose nanocrystals and xyloglucan, a common hemicelluloses present in dicotyledons. By deposition of this 2D films on templates like emulsion droplets or vesicles, artificial plant cells, at least simplified models with spherical shape, can be obtained. A great number of parameters can be then modified in a controlled manner, like the nature of the hemicelluloses, their potential covalent binding to cellulose and the deposition method in presence of external constraints.

In a totally different domain, the self-organization of cellulose nanocrystals in chiral nematic structures can be used to reproduce the helical structures that can be found in certain organisms. By tuning the interaction between the particles and using external fields, it is possible to mimick the iridescent properties exhibited by the beetle shells or some plants like the Pollia fruit.

Evènement(s) associé(s)