Smart light-triggered thermo-responsive superwetting CoZn-ZIF decorated PVDF/PNIPAM@GO nanofiber membranes for switchable oil-water emulsion separation

Efficient separation of oil–water emulsion remains a persistent challenge in wastewater treatment, as conventional membranes often suffer from fouling, poor recyclability, and lack of dynamic control. Here, we report a light-triggered thermo-responsive superwetting nanofiber membrane (PPZ@GO) that combines electrospun PNIPAM/PVDF nanofibers with graphene oxide (GO) and in situ grown bimetallic CoZn–ZIF frameworks. In this hybrid design, PVDF provides mechanical robustness, PNIPAM enables reversible thermo-responsive wettability, GO facilitates rapid photothermal heating, and CoZn–ZIF imparts hierarchical roughness and enhanced interfacial functionality. The optimized [email protected]  % membrane exhibits rapid photothermal heating to 48.6 °C within 20 s under simulated solar light, enabling reversible wettability switching between underwater superoleophobicity (light off, below LCST) and under-oil superhydrophobicity (light on, above LCST). This dual-mode response allows on-demand separation of both oil-in-water and water-in-oil emulsions, achieving fluxes above 2000 L m −2  h −1 and 1000 L m −2  h −1 , respectively, with separation efficiencies exceeding 99 %. The membrane further demonstrates excellent antifouling resistance, mechanical durability, and stable performance across repeated cycles. By integrating photothermal conversion with thermo-responsive switching in a nanofibrous MOF–polymer scaffold, this work provides a versatile strategy for designing smart, energy-efficient membranes, offering broad potential for next-generation oily wastewater remediation and advanced separation technologies.