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Post-Doctoral Position « From the Nanostructure and the mechanics of NanoFibrils of Cellulose to the Gel-like Rheology of Concentrated NFC Suspensions »

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Project summary

Nanofibrils of cellulose (NFCs) are biosourced nanofibers that exhibit outstanding morphological and mechanical properties. They can be used as an elementary brick for bio-based alternative materials in several engineering and industrial domains (transportation, automotive, energy, packaging, cosmetic and so on). However, the forming of NFC-based nanopapers or nanocomposites using processing routes such as film casting, injection, extrusion, or compression molding, induces several rheological problems, e.g. uncontrolled flow-induced deformation and organization of NFCs in their aqueous or polymeric suspending fluids: NFC suspensions exhibit a complex gel-like rheology which is still not well understood. In this project, we propose to tackle this problem using a novel multiscale methodology, with a particular focus on the elastic properties and the yield stress of concentrated NFC suspensions. For that purpose:• The nanostructure of NFCs, with straight crystalline zones and kinks, and their mechanical behavior will be investigated using atomistic Molecular Dynamics simulations. The investigated mechanical NFC loadings will constitute an original database, thus enabling a new NFC beam model to be proposed.• The beam model will be implemented into a Discrete Element code dedicated to the mechanics of fibrous materials. Thus, realistic NFC networks will be generated with different NFC contents and orientations. Simulation will be performed to analyze for the anisotropic viscoelastoplastic properties of NFC suspensions.

 

Location and practical aspects

The project is a collaborative work between scientists from Univ. Grenoble Alpes and Univ. Lyon (France): Laurent Orgéas (3SR Lab, https://www.3sr-grenoble.fr/), Karim Mazeau and Yoshiharu Nishiyama (CERMAV, https://www.cermav.cnrs.fr/), David Rodney (ILM, http://ilm.univ-lyon1.fr/), Pierre Dumont and Florian Martoïa (LaMCoS, http://lamcos.insa-lyon.fr/). The proposed research team gathers experts from (i) polysaccharides such as NFCs, (ii) physics and mechanics of soft materials, with recognized skills in the fields of multiscale characterization and simulation of NFC-based and/or fibrous materials. This constitutes a valuable asset for the success of the project.The present offer is a 1 year post-doc fellowship. The successful applicant will be mainly located at the 3SR Lab and will also have to spend time in the other aforementioned labs.

We are looking for a candidate with good expertise in modelling and simulation in materials science, with a good experience with MD and/or DEM methods. Expertise in the rheology of soft-glassy materials and/or nanofibrous materials will be a “plus”.

 

Applications

Interested candidates should send electronic applications to Laurent.Orgeas@3sr-grenoble.fr. The application documents should include a cover letter describing interests and qualifications for the position, a complete curriculum vitae including a list of publications, names and e-mail addresses of two referees.

Lieu: 
Univ. Grenoble Alpes and Univ. Lyon (France)
Contact: 
Laurent.Orgeas@3sr-grenoble.fr