Impact of mechanical confinement on permeation in polymeric membranes

Transport of chemical species in polymeric materials is met in many industrial applications in the energy sector. It is often related to the performance of a process or an equipment. So understanding, predicting and mastering this phenomenon is a subject of first importance to gain in efficiency in these sectors, and offers many industrial opportunities.
Transport of chemical species in polymers involves several coupled physical mechanisms that are related  to the interactions of species within the material. In particular, the species must dissolve in the matrix before diffusing. This solubilization modifies the local properties of the matrix and can cause swelling. Accordingly, the permeation will be different depending on whether the material is constrained or free to swell. The impact of this mechanical stress on transport properties is the key point that we propose to study extensively during the thesis.
Based on accurate analysis and description of the physical mechanisms encountered, the objective of the PhD is to develop a modeling strategy for molecular transport in these deformable solids. A rigorous formalism has to be developed. It could be based on the Maxwell-Stefan diffusion equations, using the gradient of the chemical potentials obtained by an equation of state, with the addition of the suitable mechanical component. The development of a numerical tool should make it possible to reproduce available experimental data. Additional measures may be considered. This work will be carried out in partnership with the team of Professor Eric Favre, at ENSIC (France).

Keywords: Permeation, Diffusion, Swelling, Polymer, Thermodynamic

Academic supervisor    Dr., de HEMPTINNE, Jean-Charles, IFPEN, Thermodynamic and Molecular Simulation Department, https://orcid.org/0000-0003-1607-3960
Doctoral School    Chimie Physique et Chimie Analytique de Paris Centre, http://www.ed388.upmc.fr/fr/index.html
IFPEN supervisor    Dr., LEFEBVRE, Xavier, Physical Chemistry of Complex fluids and Materials Department, xavier.lefebvre@ifpen.fr
PhD location    IFP Energies nouvelles, Rueil-Malmaison, France, with periods at Université de Lorraine (Nancy - France)
Duration and start date    3 years, starting in fourth quarter 2021
Employer    IFP Energies nouvelles, Rueil-Malmaison, France
Academic requirements    University Master degree in Materials or Chemical Eng., Thermodynamic 
Language requirements    Fluency in French or English with willingness to learn French
Other requirements    Experience appreciated in programing and use of modelling software (Comsol, Abaqus, …).