Oil-soluble surfactant regulated interfacial polymerization toward homogeneous fluorinated membranes for crude oil separation

Membrane separations without phase transition offer a compelling route to low-energy crude oil fractionation. For practical implementation, membranes are required to simultaneously achieve high permeance, sharp molecular sieving and long-term structural stability in hydrocarbon media. Herein, we report the rational design of homogeneous polyamide membranes for crude oil separation, fabricated via oil-soluble surfactant mediated interfacial polymerization by synergistic integration of hydrophobic monomers. The rigid fluorinated monomer improves membrane compatibility with hydrocarbons, while oil-soluble surfactants with varying chain lengths enable the regulation of pore size distribution, yielding a wrinkled and ultrathin selective layer. The modulated membrane exhibits precise sieving of small solutes, showing a high toluene/triisopropylbenzene separation factor of ∼14 and excellent permeance of ∼8.4 L m -2 h -1 bar -1 . Importantly, the membrane retains superior selectivity for light crude oil separation, enabling effective retention of heavy components and delivering a light permeate with lower boiling point distribution. This work advances the development of sustainable membrane technologies for efficient crude oil separation.