Dynamic Sub‐Nanoscale “Water Fingers” in Interfacial Polymerization
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.
Authors
- Jinkai Yuan (ORCID: https://orcid.org/0000-0003-2347-5191)
- Wenming Fu (ORCID: https://orcid.org/0000-0002-7823-1875)
- Tomohisa Yoshioka (ORCID: https://orcid.org/0000-0002-7489-441X)
- Tianmu Yuan (ORCID: https://orcid.org/0000-0002-3737-3885)
- Junyong Zhu (ORCID: https://orcid.org/0000-0002-1200-715X)
- Hideto Matsuyama (ORCID: https://orcid.org/0000-0003-2468-4905)
- Zhaohuan Mai (ORCID: https://orcid.org/0000-0002-8388-4029)
- John H. Lienhard (ORCID: https://orcid.org/0000-0002-2901-0638)
- Ralph Rolly Gonzales (ORCID: https://orcid.org/0000-0002-2175-2944)
- Yongxuan Shi (ORCID: https://orcid.org/0000-0002-8719-2070)
- Kecheng Guan (ORCID: https://orcid.org/0000-0002-4924-7480)
- Akshay Deshmukh (ORCID: https://orcid.org/0000-0002-3693-1902)
- Zhan Li (ORCID: https://orcid.org/0000-0003-0576-1936)
- Pengfei Zhang (ORCID: https://orcid.org/0009-0008-1541-945X)
- Arata Yamamoto
Institutions
- Centre National de la Recherche Scientifique (FR)
- University of Manchester (GB)
- Zhengzhou University (CN)
- Sorbonne Université (FR)
- Chimie de la Matière Condensée de Paris (FR)
- Massachusetts Institute of Technology (US)
- Kobe University (JP)
Publication Details
- Journal
- Small
- Published
- 2025-06-20
- DOI
- https://doi.org/10.1002/smll.202504497
- Citations
- 6
- Primary Topic
- Membrane Separation Technologies
- Type
- article
- Field-Weighted Citation Impact
- 4.90
Funders
- Japan Society for the Promotion of Science