Description :
Description
The Goal of this project is to use a membrane separation process combined with reticulation UV to develop new controlled oriented cellulosic nanocomposites with reinforced and optimized functional properties.

An important aspect for the development of new controlled oriented nano-structured biomaterials is a deep understanding and control of the organization induced during theirs processing. One of the main limitations to produce homogeneous oriented structures is to achieve a proper control of the balance between external forces (shear flow, extensional flow, pressure) and internal colloidal forces during their processing. It was recently revealed using cross-flow ultrafiltration process and in-situ SAXS that this limitation can be overcome. Indeed, during this process, the shear flow applied at low volume fraction (below the sol-gel transition) allows inducing sufficient orientation of anisotropic particles. From this oriented state the particles are then simultaneously deposited and concentrated above the sol-gel transition by the transmembrane pressure, forming highly regular oriented colloidal materials[1-3].

The main task of this post-doc position will be to perform ultrafiltration process with in-situ UV curing on (nanoparticles/UV cured polymer) suspensions, in order to fabricate nanocomposites thin films (thickness from tens to hundreds of µm). The structural organization of these nanocomposites, will be characterized ex-situ by MEB and TEM or in-situ by SAXS, and should be linked to macroscopic characterization of the functional properties of the nanocomposites (mechanical, electrical and barrier properties).

Several suspensions will be studied. Firstly, UV cured polymer matrix will be mixed with different nanocelluloses (nanocrystals or nanofibers). Secondly, these cellulosic–UV cured polymer systems will be combined with others kinds of nanoparticles as graphite, graphene, carbon nanotubes, clays or self-assembled milk protein nanofibers in order to reach specific functional mechanical, electrical, or barrier properties.
The present offer is 1 year post-doc fellowship.

Start date : February 2017
The work will be mainly located at the (LRP, http://www.laboratoire-rheologie-et...) and will be supervised by Frederic Pignon (with the help of Nicolas Hengl and Hugues Bodiguel).

This project has received the financial support of the Carnot Polynat (http://www.polynat.eu/en).

It is a collaborative work with 3 others Laboratory located near the LRP, which will bring a joint expertise and a common work, thanks to three accompanying trainees (6 months each). Theirs tasks will be firstly the formulation, the control of physico-chemical properties and stability of the UV cured polymer-nanoparticles suspensions, and secondly, the characterizations of mechanical, electrical and barrier properties.

Consequently, the Post-doc would have to spend some times in the others Laboratory : with Michael Holzinger (DCM, http://dcm.ujf-grenoble.fr/DCM-SITE/DCM/, BEA team) Bruno Jean and Jean-Luc Putaux (Cermav, https://www.cermav.cnrs.fr/) and Didier Chaussy, Davide Beneventi and Julien Bras (LGP2, http://pagora.grenoble-inp.fr/resea...).

Qualifications : the applicants must hold a Ph.D. in soft condensed matter, or in chemical engineering. Strong skills and experience in structural and/or mechanical characterization of colloids and polymers, eventually an expertise in membrane separation processes would be appreciated.

Applications : Interested candidates should contact F. Pignon at this e-mail address : frederic.pignon@univ-grenoble-alpes.fr with a complete curriculum vitae, publication list and a cover letter describing the motivations and qualifications in accordance with the position.

Réferences :
[1] Pignon F. et al., “In Situ Characterization by SAXS of Concentration Polarization Layers during Cross-Flow Ultrafiltration of Laponite Dispersions”, Langmuir, 28, 1083-1094, (2012).
[2] Jin Y. et al., “Effects of ultrasound on colloidal organization at nanometer length scale during cross-flow ultrafiltration probed by in-situ SAXS”, J. Memb. Sci., 453, 624-635, (2014).
[3] Jin Y. et al., “Ultrasonic assisted cross-flow ultrafiltration of starch and cellulose nanocrystals suspensions : Characterization at multi-scales”, Carbohydrate Polymers, 124, 66-76, (2015).

Reference : Post-Doc - NanoCompUV

Date de démarrage : 02 février 2017

Durée : 12 months

Contacter :
Laboratoire Rhéologie et Procédés, http://www.laboratoire-rheologie-et...
Frédéric Pignon
Laboratoire Rhéologie et Procédés BP 53, Domaine Universitaire, 38041 Grenoble Cedex 9, France
email : frederic.pignon@univ-grenoble-alpes.fr
Téléphone : 33 456520195

Page web : http://sites.google.com/site/fredericpignon/