Laboratoire Charles Coulomb UMR 5221 CNRS/UM2 (L2C)

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POSTDOCTORAL POSITION – 24 months Structure, dynamics and rheology of gluten under large strain

par Christelle EVE - publié le

Laboratoire Charles Coulomb, Université de Montpellier, France.

Biopolymer gels can display intriguing mechanical response when submitted to an extreme deformation. In this framework, biopolymer gels made from wheat gluten proteins may exhibit under a mechanical stress a sudden and unpredictable strong softening. Their original properties can be partially recovered after a rest time once the stress released, indicating the transient character of the bonds affected by the stress. The objective of the project is to characterize and rationalize the behavior under, and after, large deformation of elastomeric gluten gels, in order to elucidate the biochemical, physicochemical and physical mechanisms at the origin of the catastrophic response under stress. The main challenge is to unravel the respective roles of disulfides bonds and hydrogen bonds in the strain induced network breaking and the subsequent recovery at rest. The non-linear rheology of model gluten samples designed with different strategies to label and control the disulfide and the hydrogen bond exchanges will be characterized. Then, state of the art advanced soft matter techniques in addition to original spectroscopic and biochemistry approaches will be used. The multi-scale structure and dynamics of the gluten network submitted to non-linear shear stress and its recovery after large strain cycles will be investigated in situ using Small Angle Neutron Scattering, vibrational spectroscopies (Raman, Infrared), diffusing wave spectroscopy and X-ray photon correlation spectroscopy. Hence, we will be able to establish a relationship between the microscopic dynamics, the microscopic structure and the macroscopic rheology of samples during shear in the non-linear regime and after a mechanical perturbation. The project gathers a multidisciplinary team with strong expertise in soft matter physics, physical-chemistry, spectroscopy and biochemistry. We expect our results to have impacts in the fundamental understanding of the mechanical response of polymer networks with transient bonds and in technology-related fields as gluten is widely used in food industry.

We are seeking a highly motivated candidate for a 24-months postdoctoral position. The project will be performed in collaboration with A. Banc, L. Ramos, L. Cipelletti from L2C (CNRS/University of Montpellier), and M-H Morel from the IATE laboratory (INRA/Supagro). Interested applicant should send a cover letter, a complete CV with a publication list and 2 academic references (with address, phone number and email).

Starting : negotiable, from February 2019.
Profile  : PhD in Soft Matter Physics. Experiences in non-linear rheology and/or dynamic scattering would be appreciated.
Contact :amelie.banc@umontpellier.fr (+33 4 67 14 34 37)


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