Ultraselective Amino–Phenolic Nanofiltration Membranes via Enzyme-Mediated Decoupling of Diffusion and Reaction

Polymer membranes are essential in separation processes such as desalination and organic solvent nanofiltration. However, simultaneously manipulating subnanometer pore size, homogeneity, and chemistry remains challenging due to the coupled diffusion-reaction of building blocks in membrane formation, resulting in the trade-off between permeance and selectivity. Here, we report a versatile enzyme-mediated strategy that kinetically decouples diffusion and reaction, enabling multidimensional pore engineering with tunable pore sizes (0.43-0.84 nm), improved homogeneity, and modular surface chemistry across eight polyamine-phenolic combinations. Phenolics with desired moieties diffuse uniformly into polyamine branch voids and create enzyme-regulated pores, forming highly homogenized and chemically tailored selective layers with ultraselectivity of ∼30 toward solutes with molecular weights below 350 Da, outperforming state-of-the-art membranes (selectivity <10). In high-value pharmaceutical separation, these membranes further achieve 1 order of magnitude higher selectivity, a 7.3-fold increase in solvent permeance, and a 6.8-fold improvement in enrichment efficiency compared to commercial membranes. By highlighting the importance of multidimensional pore engineering in improving membrane selectivity and permeability, our work suggests a pathway for unlocking the potential of polymer nanofiltration membranes for accurate molecular sieving applications.