Regulation of Oil/Water Separation Using Pyridinium-Based Poly(ionic liquid)s with Prewetted Induced Responsive Transition

The development of affordable, intelligent dual-separation technology is crucial for the treatment of oil–water mixtures. Pyridinium-based poly(ionic liquid)s (PILs), designed using molecular theory, exhibit unique switching wettability properties, making them ideal for use in both aqueous and oily environments. By prewetting the material's surface with water or oil, the targeted separation of these components becomes feasible. PILs are synthesized through the cross-linking of [Pyr]Cl with various cross-linkers and auxiliary agents. Studies on the wetting mechanism of these materials have identified bursting pressure and surface structure as key factors influencing their wetting properties. They exhibit hydrophilic and lipophilic properties in air, hydrophobic properties under oil, and oleophobic properties under water, achieving a 99% separation efficiency. A reusability study demonstrated maintenance of 90% efficiency after 10 cycles, highlighting their sustained high performance. This research presents promising avenues for the application of PIL-based materials in oil–water separation, environmental remediation, and industrial processing.