Tailor-made structure and morphology are critical to the highly permeable and selective polyamide membranes used for water purification. Here we report an asymmetric polyamide nanofilm having a two-layer structure, in which the lower is a spherical polyamide dendrimer porous layer, and the upper is a polyamide dense layer with highly ordered nanovoids structure. The dendrimer porous layer was covalently assembled in situ on the surface of the polysulfone (PSF) support by a diazotization-coupling reaction, and then the asymmetric polyamide nanofilm with highly ordered hollow nanostrips structure was formed by interfacial polymerization (IP) thereon. Tuning the number of the spherical dendrimer porous layers and IP time enabled control of the nanostrips morphology in the polyamide nanofilm. The asymmetric polyamide membrane exhibits a water flux of 3.7−4.3 times that of the traditional monolayer polyamide membrane, showing an improved divalent salt rejection rate (more than 99%), which thus surpasses the upper bound line of the permeability−selectivity performance of the existing various structural polyamide membranes. We estimate that this work might inspire the preparation of highly permeable and selective reverse osmosis (RO), organic solvent nanofiltration (OSNF) and pervaporation (PV) membranes.

Novel Ti ₃ C ₂ /polyacrylamide nanocomposite hydrogels with excellent mechanical and drug release performances were fabricated via in situ polymerization, employing ultralow content Ti ₃ C ₂ nanosheets as crosslinkers instead of organic crosslinkers.

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.