Feedback-controlled molecular transport through responsive polymer membranes

• Applicant: Professor Dr. Joachim Dzubiella
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Experimental and Theoretical Physics of Polymers
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431945604

The transport of molecular solutes through dense polymeric membranes is of key importance for applications like gas separation, desalination and nanofiltration (”molecular sieving”), or medical treatments by dialysis or selective drug delivery. In standard theoretical approaches the transport is modeled on a linear response level, i.e., fluxes are assumed to be simply proportional to the driving fields or chemical gradients and the membrane permeability is estimated from equilibrium solvation and fluctuation behavior of the membrane. However, modern materials used, e.g., thermosensitive polymers, display a complex nonlinear response and feedback behavior, and linear transport theory is expected to break down. part of the Research Unit "Reducing complexity of nonequilibrium Systems", the goal of this project is to understand non-equilibrium and feedback-influenced transport of solutes driven through responsive polymer membranes and will thus extend the important concept of permeability to highly non-linear, non-equilibrium situations. This will be studied in one part directly by implicit-solvent but "microscopic", i.e., monomer-resolved Langevin simulations of transport in polymer networks, and will be complemented by the development of the appropriate non-equilibrium theories with various (reduced) degrees of coarse-graining. Such a reduction of complexity in, e.g., Fokker-Planck and stochastic Langevin frameworks will lead to new and proper definitions for membrane permeability and flux-force responses in non-equilibrium situations, and will thus help shaping new materials.

• DFG Programme: Research Units
• Subproject of: FOR 5099: Reducing complexity of nonequilibrium systems
• Co-Investigator: Professorin Dr. Tanja Schilling