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.