Lithium extraction from salt lake brines is highly demanded to circumvent the lithium supply shortage. However, polymer nanofiltration membranes suffer from low lithium permeability while nanofluidic devices are hindered by complicated preparation and miniaturized scales despite high permeability. Here, the authors report a facile strategy to prepare positively charged nanofiltration membranes for ultrapermeable and selective separation of lithium ions from concentrated magnesium/lithium mixtures. A new electrolyte monomer (diaminoethimidazole bromide, DAIB) containing bidentate amine groups is designed to modify pristine polyamide composite membranes. Structure characterizations and simulations show that the DAIB modification brings about nano-heterogeneity that not only improves surface hydrophilicity, but also reduces water transport resistance through the ≈100 nm thick separation layer. Water permeance of the modified membrane improves fivefold and is coupled with good stability in 200-h continuous nanofiltration. It exhibits high lithium flux (0.7 mol m −2 h −1) for brines (Mg 2+ /Li + ratio 20) at 6 bar operation pressure.

Water transport rate in network membranes is inversely correlated to thickness, thus superior permeance is achievable with ultrathin membranes prepared by complicated methods circumventing nanofilm weakness and defects. Conferring ultrahigh permeance to easily prepared thicker membranes remains challenging. Here, a tetrakis(hydroxymethyl) phosphonium chloride (THPC) monomer is discovered that enables straightforward modification of polyamide composite membranes. Water permeance of the modified membrane is ≈6 times improved, give rising to permeability (permeance × thickness) one magnitude higher than state‐of‐the‐art polymer nanofiltration membranes. Meanwhile, the membrane exhibits good rejection (RNa2SO4 = 98%) and antibacterial properties under crossflow conditions. THPC modification not only improves membrane hydrophilicity, but also creates additional angstrom‐scale channels in polyamide membranes for unimpeded transport of water. This unique mechanism provides a paradigm shift in facile preparation of ultrapermeable membranes with unreduced thickness for clean water and desalination.

Polymer crosslinking is crucial for the preparation and consolidation of hierarchical nano- and microstructures, hybrid interfaces, and collective assembly. Here for the first time we show that a “cation–methylene–nitrile” functionality...

Appropriate deciphering and translation of sequence-dependent function inproteins is inspired by the cation-π interaction that is increasingly implicated in marine adhesives and membraneless organelles. A simplified cation-methylene-phenyl (C-M-P) sequence which enables triggerable poly(ionic liquid) coacervation is reported for the first time. Synthesis of the C-M-P structure motif requires only a one-step quaternization, which is facile compared to the linear sequence of distinct repeating units in model proteins and sequencecontrolled polymers. The C-M-P code confers modular coacervation and advanced wet adhesion to task-specific copolymers. It allows for exceptional underwater adhesion to various submerged substrates including glass (≈1 MPa) and porcine skins (140 KPa), paving the way for prospective adhesive applications in physiological saline and underwater marine salvage. This work introduces a powerful code that, in addition to combining the advantageous adaptive adhesive and phase properties of proteins, reduces the complexity in sequence design for programmable coacervates.

The water nanofluidics in confined channels has endowed pressure-driven separation membranes with superior permeability. However, nanofluidic effect in solar-thermal steaming materials is hindered by discrete heat absorbers and nanochannels. Here...

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Lignin‐carbohydrate complexes (LCC) underpin the comprehensive properties of natural wood. Facile restoration of LCC analogues in paper is challenging because of the charge repulsion between negatively charged lignin and pulp fibrils. A camouflage strategy is discovered to prepare positively charged lignosulfonate–polyamide‐epichlorohydrin complex (LPC) nanoparticles, which are effectively incorporated in pulp through the “LPC–pulp” attraction instead of “lignosulfonate–pulp” repulsion. Water‐resistant LPC paper sheets are prepared in ≈20 min without pressurization. They exhibit high tensile strength (41 MPa), surviving boiling water treatment for 14 days, on par with the strength of pristine paper and certain plastics in a dry state. The camouflage strategy applies to various pulps and processing technologies, as exemplified by a paper separator showing exceptional electrolyte wettability and rate capability in lithium‐ion batteries. This work establishes advanced cellulose valorization with combined strength, water stability, and tailored microstructures replacing petroleum polymers in engineering and energy implications.

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