Permeability Maximization of Polymer Networks

Permeability measures the ability of a material, such as a polymer network (hydrogel), to transport molecular solvents and solutes and defines an important control parameter in soft functional material applications, e.g., filtration, drug release, and transport of reactants in responsive nanoreactors [1-4]. We calculate permeabilities by means of coarse-grained simulations and theory of a model polymer network. We find that the permeability can be maximized by optimal polymer volume fractions and inter-particle interactions between the polymer and the penetrating solutes. This nontrivial phenomenon is triggered by a competition between solute partitioning [1-3] and diffusion [2]. Throughout a wide range of parameter space of solvent quality, solute coupling, and gel volume fraction, a rich topology of the partitioning is found. The solutes' diffusivity is highly correlated to gel structures, resulting in a drastically nonmonotonous permeability. Possible applications to hydrogel based devices such as responsive nanoreactors for catalysis [2,4] are discussed.

[1] Kim et al. Macromolecules 50, 6227 (2017).
[2] Roa et al. ACS Catalysis 7, 5604 (2017).
[3] Kanduč et al. Phys. Chem. Chem. Phys. 19, 5906 (2017).
[4] Wu et al. Angewandte Chemie 51, 2229 (2012).