Mai Zhaohuan, Yoshioka Tomohisa, Deshmukh Akshay, Yuan Tianmu, Zhu Junyong, Yuan Jinkai, Gonzales Ralph Rolly, Yamamoto Ayano, Shi Yongxuan, Fu Wenming, Guan Kecheng, Li Zhan, Zhang Pengfei, Lienhard John H, Matsuyama Hideto
Research Center for Membrane and Film Technology, Kobe University, Kobe, 657-8501, Japan.
Graduate School of Science, Technology and Innovation, Kobe University, Kobe, 657-8501, Japan.
Small. 2025 Aug;21(33):e2504497. doi: 10.1002/smll.202504497. Epub 2025 Jun 20.
Interfacial polymerization (IP) is widely used to fabricate high-performance membranes, yet the molecular-level dynamics that govern monomer transport across liquid-liquid interfaces remain poorly understood. Here it is reported that sub-nanoscale "water fingers"-transient chains of water molecules-modulate the interfacial behavior of amine monomers during IP, dictating the structure and performance of the resulting polyamide films. Using molecular dynamics simulations of archetypal membrane-forming systems (m-phenylenediamine (MPD)-trimesoyl chloride (TMC) for reverse osmosis and piperazine (PIP)-TMC for nanofiltration), it is revealed that water fingers differentially stabilize monomer transport across the aqueous-organic interface, correlating with experimentally observed disparities in film density and permeability. These findings offer a new physical picture of interfacial reactivity, establishing water fingers as critical, tunable elements of monomer transport. This work provides mechanistic insights into a century-old reaction and opens new design strategies for ultrathin films and interfacial materials.
界面聚合（IP）被广泛用于制备高性能膜，然而，控制单体跨液 - 液界面传输的分子水平动力学仍知之甚少。本文报道，亚纳米级的“水指”——水分子的瞬态链——在界面聚合过程中调节胺单体的界面行为，决定了所得聚酰胺膜的结构和性能。通过对典型的成膜体系（用于反渗透的间苯二胺（MPD） - 均苯三甲酰氯（TMC）和用于纳滤的哌嗪（PIP） - TMC）进行分子动力学模拟，发现水指以不同方式稳定单体跨水 - 有机界面的传输，这与实验观察到的膜密度和渗透率差异相关。这些发现提供了界面反应性的新物理图景，将水指确立为单体传输的关键且可调节的要素。这项工作为一个百年老反应提供了机理见解，并为超薄膜和界面材料开辟了新的设计策略。
