(187aq) Modeling Equilibrium and Diffusion Processes with Polymeric Lyogel Structures in Multicomponent Solutions Using PC-SAFT

Some polymeric gel structures exhibit a variety of remarkable properties, such as a strong swelling and collapsing behavior for specific external stimuli like temperature, solvent concentration and pH-value. This has led to their classification as smart lyogels or stimuli-responsive lyogels. Those gels are under active research and there are numerous publications on industrial application [1] and experimental findings. [2]

In recent years, the modeling approaches relying on physics-informed equations of state such as PC-SAFT gained more attention due to their promising ability to accurately describe responsive effects like swelling behavior. [3] The use of an equation of state does not only allow the calculation of the final equilibrium state, but it also grants insight to the thermodynamic driving forces which arise within the swelling process. Together with the Maxwell-Stefan diffusion, a physics based kinetic description of the macroscopic swelling process can be established. [4]

Here, we extend these methods to analyze both temperature- and solvent-induced swelling in multicomponent solutions, addressing additional phenomena such as solvent exchange and cononsolvency effects. By integrating this, our work offers a comprehensive framework to describe the diffusion processes within gels, paving the way for a more robust and predictive understanding of stimuli-responsive gel systems.

This project is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – SFB 1615 – 503850735

References:

[1] Hu, X. et al., Chemical Engineering Journal 387, 123413 (2020).

[2] Eckert, K. M., et al., Fluid Phase Equilibria 586, 114182 (2024).

[3] Arndt, M. C. & Sadowski, G., Macromolecules 45, 6686–6696 (2012).

[4] Wagner, S. et al., Fluid Phase Equilibria 594, 114393 (2025).