Confined Channels Induced Coalescence Demulsification and Slippery Interfaces Constructed Fouling Resist-Release for Long-Lasting Oil/Water Separation

Superwetting membranes based on steric exclusion and affinity difference have drawn substantial interest for oil/water separation. However, the state-of-the-art membranes fail to literally sort out fouling and permeability decline and so limit their viability for long-term separation. Inspired by Dayu’s philosophy of “draining rather than blocking water”, herein, we achieve a long-lasting and efficient separation for viscous emulsions by designing poly(hydroxyethyl methylacrylate) (PHEMA)- and polydimethylsiloxane (PDMS)-compensated poly(vinylidene fluoride) membranes based on coalescence demulsification via chemical coordination phase separation. The symmetric and torturous microporous structure facilitated oil spatial confining and coalescence demulsification, while the synergistic compensation of PHEMA and PDMS coordinated the fouling resist and release properties, which was confirmed by multichannel confocal laser scanning microscopy. The developed membrane shows an unprecedented permeability half-life (τ) for viscous emulsions (e.g., decamethylcyclopentasiloxane, soybean oil paraffin, n-hexadecane, and isooctane) under cross-flow operation, far more beyond common superwetting membranes under applied bench-scale dead-end filtration. Our technique for designing “nonfouling” membranes opens up opportunities for advancing next-generation membranes for oil/water separation.