Water Molecule as a Dynamic Cross-Linker for Creating Multifunctional Poly(ionic liquid) Porous Membranes

Supramolecular polyelectrolyte porous membranes (SPPMs), which structurally integrate supramolecular material properties, electrolyte characteristics and pore confinement effects into a membrane, represent an exciting class of materials targeted for a broad range of applications in modern science and technology. However, owing to the intrinsic water solubility of conventional polyelectrolytes and the complex bonding mode arising from their charged nature, a long-standing challenge in the field has been the development of reliable preparation methods for fabricating high-quality SPPMs with controllable pore architectures and programmable functionalities. There have been a few characteristic attempts at achieving SPPMs. One involves layer-by-layer assembly of polyelectrolyte species through the strategic utilization of “orthogonal” noncovalent interactions; the other involves self-assembly of amphiphilic polyelectrolyte block copolymers, forming SPPMs. However, considering the multiple tedious preparation steps, the use of large amounts of organic solvents, and/or expensive precursors, these approaches suffer from some inherent limitations for the scalable preparation of SPPMs. Undoubtedly, direct assembly of polyelectrolytes in water to produce SPPMs is a priority because of its eco-friendly nature and ease of scaling up.