The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m⁻² h⁻¹ bar⁻¹, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation.

开发阻断溶质同时允许快速水传输的膜非常重要。膜的微观结构需要在分子水平上进行合理设计，才能同时实现精确的分子筛分和高水通量。我们报告了通过化学气相沉积设计和制造厚度低至 1 nm 的超薄有序共轭聚合物骨架 (CPF) 薄膜及其作为分离膜的性能。我们的 CPF 膜固有地具有规则的菱形亚纳米 (10.3 × 3.7 Å) 通道，这与由碳纳米管或石墨烯制成的膜不同，后者的分离性能取决于材料的排列或堆叠。优化后的膜表现出高达~ 6,900的高水/NaCl 选择性和~112 mol m ^-2  h ^-1  bar ^-1，在渗透压驱动的高盐度混合离子分离中脱盐率>99.5%。分子动力学模拟表明，水分子通过在疏水通道内形成连续的三维网络，快速集体地穿过膜。有序 CPF 的出现为开发用于精确分子分离的碳基膜提供了一条途径。