Macromol. Chem. Phys. (2025), ‘‘Dynamics of Thermally Induced Phase Separation in Polyvinyl Alcohol Aqueous Solutions: Impact of Viscosity Asymmetry on Scaling’’
The ANR SIMUMEM project aims to elucidate the key mechanisms governing the fabrication of porous polymer membranes. The latter are invariably manufactured via a rapid phase separation process (quenching) of a relatively concentrated polymer solution (>10 wt%). The two separating phases can consequently exhibit very different viscosities and elasticities (by at least three orders of magnitude). In the article Macromol. Chem. Phys. (2025) (doi.org/10.1002/macp.202500083), we demonstrate that a viscosity difference alone does not fundamentally alter the onset and behavior of bicontinuous phase separation (see figure). Therefore, the viscosity difference is not the key parameter required to explain the more tortuous morphologies—frequently encountered during the still largely empirical development of filtration membranes—than those depicted in the figure.
Complementarily, in the article J. Chem. Phys. (2025) (doi.org/10.1063/5.0302095), using phase-field numerical methods (which allow phase interfaces to be treated as diffuse and continuous through the introduction of an order parameter), we investigate phase separation induced by contacting a solution with a non-solvent, whereas phase separation was temperature-induced in the previous study. It is thereby demonstrated that bicontinuous morphologies can emerge across a broad region of the parameter space.
Contact : Team NIMBE/LIONS, Patrick GUENOUN
Time evolution (from left to right) of the bicontinuous phases at three different heights (from bottom to top)