Fabrication of advanced nanofiltration membranes with nanostrand-hybrid morphology mediated by ultrafast Noria-polyethyleneimine co-deposition

Polyphenol chemistry-based surface modification has received extensive attention in membrane science for its simplicity and low-cost. However, the limited molecular structures combined with the generally time-consuming process have largely restricted their further applications. Herein, we report an ultrafast and universal surface modification strategy based on the co-deposition of a macrocycle polyphenol molecule, Noria, and polyethyleneimine (PEI), for which only several seconds are required to obtain a uniform coating. Moreover, nanofiltration membranes were fabricated by traditional interfacial polymerization (IP) using the Noria-PEI co-deposited coating as the interlayer. Interestingly, the host-guest heterogeneous interaction between anchored Noria on the support surface and amine monomers in the aqueous phase could significantly alter the IP process and contribute to a unique nanostrand-hybrid morphology for piperazine and trimesoyl chloride-based membranes. Consequently, such novel morphology-based nanofiltration membranes exhibited a high permeance of up to 28 L m(-2) h(-1) bar(-1) while still maintaining comparable divalent salt (Na2SO4, MgSO4, MgCl2 and CaCl2) rejections of above 96.0%, which are among the best performances for nanofiltration membranes. In addition to membrane science, this ultrafast surface modification strategy could arouse intense interest in host-guest chemistry at interfaces for fabricating multifunctional materials.