Interfacial polymerization (IP) and self-assembly are two thermodynamically different processes involving an interface in their systems. When the two systems are incorporated, the interface will exhibit extraordinary characteristics and generate structural and morphological transformation. In this work, an ultrapermeable polyamide (PA) reverse osmosis (RO) membrane with crumpled surface morphology and enlarged free volume was fabricated via IP reaction with the introduction of self-assembled surfactant micellar system. The mechanisms of the formation of crumpled nanostructures were elucidated via multiscale simulations. The electrostatic interactions among m -phenylenediamine (MPD) molecules, surfactant monolayer and micelles, lead to disruption of the monolayer at the interface, which in turn shapes the initial pattern formation of the PA layer. The interfacial instability brought about by these molecular interactions promotes the formation of crumpled PA layer with larger effective surface area, facilitating the enhanced water transport. This work provides valuable insights into the mechanisms of the IP process and is fundamental for exploring high-performance desalination membranes.

Nanofiltration (NF) offers a scalable and energy-efficient method for lithium extraction from salt lakes. However, the selective separation of lithium from magnesium, particularly in brines with high magnesium concentrations, remains a significant challenge due to the close similarity in their hydrated ionic radii. The limited Li⁺/Mg²⁺selectivity of current NF membranes is primarily attributed to insufficient control over pore size and surface charge. In this study, we report the development of an interlayered thin-film composite (iTFC) membrane incorporating functionalized sulfonated carrageenan to regulate the interfacial polymerization process. This integrated interlayer plays a crucial role in controlling the diffusion and spatial distribution of amine monomers, leading to the formation of dense, nano-striped polyamide networks. These structural improvements including refined pore size and reduced negative charge significantly enhanced Li⁺/Mg²⁺selectivity (133.5) and increased permeance by 2.5 times compared to conventional TFC membranes. Additionally, the nano-striped structure optimized the membrane filtration area while minimizing ion transport resistance, effectively overcoming the traditional trade-off between ion selectivity and permeability. This study highlights the potential of iTFC membranes for achieving both high lithium purity and recovery, offering a promising avenue for large-scale lithium extraction from brines.

Development of polymeric cation exchange membranes (CEMs) with high thermostability and resistance to organic solvents is an urgent challenge for materials chemistry and a major problem for industrial application. Herein, we report a novel CEM design, which symmetrically recombines poly(p-phenylene terephthalamide) nanofibers and 2,5-diaminobenzenesulfonic acid based on amide hydrolysis and amide condensation reaction for ion separation in high temperature and organic solvent aqueous applications. The resulting membrane (10 μm thickness) exhibited greater thermodynamic and electrochemical properties than the common commercial CEMs. Attributed to the membrane's specific structure, size sieving, and electrostatic repulsion effects, the resulting membrane showed a more selective separation of monovalent cations in electrodialysis. Moreover, it has demonstrated exceptional desalination at high temperature (as high as 100 °C) and organic solvent aqueous environments (as high as 80% acetone solution), which had not been previously reported in electrodialysis. The resulting membrane combines the benefits of nano-materials and a specific structure design allowing for electrodialysis in high temperature and organic solvent aqueous application environments.