High-efficiency water transport and boron removal in polyamide membranes enabled by surface-grafted self-assembled monolayer molecular brushes

JL He and JS Wu and YX Yang and H Zhang and JX He and XB Tian and XD Zhou and QY Wang and YJ Liu and QY Wang and L Li, JOURNAL OF MEMBRANE SCIENCE, 719, 123722 (2025).

DOI: 10.1016/j.memsci.2025.123722

Using molecular dynamics simulations and density functional theory, we explored a novel approach involving surface-grafted self-assembled monolayer (SAM) molecular brushes. This strategy aims to achieve high selectivity for water-boric acid transport without compromising water permeance in polyamide membranes, resulting in a significant enhancement in selectivity along with an increase in water permeance. Our study systematically illustrated the transport behavior of water and boric acid across polyamide membranes incorporating nine distinct types of surface-grafted SAM molecular brushes. Our simulations demonstrated the critical role these SAM molecular brushes play in controlling selective transport, either enhancing or reducing it. These findings revealed the interaction between the SAMs molecular brushes and both water and boric acid, highlighting their impact on the water and boric acid transport mechanism. Overall, our findings suggested that rational integration of SAM-grafted molecular brushes into membrane surfaces can effectively disrupt water-boric acid interactions, decouple their migration, and achieve efficient selective transport without sacrificing water permeability. These molecular-level insights support the advancement and design of high-performance polymer membranes for small molecule separation applications.

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