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Interfacial polymerization is a well-known process to synthesize separation layers for thin film composite membranes at an immiscible organic liquid–aqueous liquid interface. The organic–aqueous interface determines the diffusion dynamics of monomers and the chemical environment for polymerization, exerting a critical influence on the formation of polymer thin films. This review summarizes recent advances in tailoring interfacial polymerization using interfaces beyond the conventional alkane–water interface to achieve high-performance separation films with designed structures. Diverse liquid–liquid interfaces are introduced for synthesizing separation films by adding co-solvents into the organic phase and/or the aqueous phase, respectively, or by replacing one of the liquid phases with other solvents. Innovative liquid–gel and liquid–gas interfaces are then summarized for the synthesis of polymer thin films for separation. Novel strategies to form reaction interfaces, such as spray-coating, are also presented and discussed. In addition, we discuss the details of how a physically or chemically patterned substrate affects interfacial polymerization. Finally, the potential of unconventional interfaces in interfacial polymerization is forecast with both challenges and opportunities. [ABSTRACT FROM AUTHOR]

Polyamide thin-film composite (TFC) membranes present a promising option for organic solvent nanofiltration (OSN) due to their superior advantages in facile fabrication and high separation efficiency. However, existing TFC-based OSN membranes are heavily limited by their weak interfacial stability in organic solvents, because many solvent-resistant porous supports are hydrophobic and have poor interfacial compatibility to polyamide. Herein, we report a polyamide TFC membrane with enhanced interfacial stability and durable OSN performance, by multifunctional surface modification and in-situ interfacial polymerization on a hydrophobic and solvent-resistant polypropylene substrate. Distinct from nascent ones, the polypropylene substrates modified by tannic acid/aminopropyltriethoxysilane coating possess excellent hydrophilicity and more functional groups, in which the former allows for the in-situ synthesis of integral polyamide layers via interfacial polymerization and the latter greatly enhances the binding strength between the polyamide layer and PP substrate by 30 times. With this method, the TFC membranes exhibit excellent thermal stability in 80 °C dimethylformamide solution. Meanwhile, the TFC membranes display high ethanol permeance (9.2 L m−2 h−1 bar−1) and acid fuchsin rejection (98.5 %), outperforming the performance of most OSN membranes reported. This straightforward method, robust structural stability, and extraordinary performance make the TFC membranes a step closer to commercial OSN membranes. [Display omitted] • Robust TFC OSN membranes are prepared by multifunctional surface modification and in-situ interfacial polymerization. • Interfacial binding strength of the TFC membranes reaches up to 180 N/m. • The TFC membranes perform good resistance toward 80 °C dimethylformamide. • The TFC membranes show an ethanol permeance of 9.2 L m−2 h−1 bar−1 and 98 % dye rejection. [ABSTRACT FROM AUTHOR]

It is still a task to synthesize polyamide‐based membranes with selective layers down to 10–20 nm for high performance desalination. Herein, cellulose nanocrystals (CNC) were used as one‐dimensional (1D) nanorods and graphene oxides (GO) as two‐dimensional (2D) nanosheets, respectively, to construct nanocomposite interlayers for synthesizing polyamide layers thinner than 15 nm. The 2D nanosheets are homogeneously mixed with the 1D nanorods and effectively reduce the surface roughness of the nanocomposite interlayers with decreasing the mass ratio of CNC/GO. Polyamide layers with a thickness of 10–15 nm have been synthesized at an ultralow monomer concentration of 0.025 wt% on these CNC/GO nanocomposite interlayers. The polyamide‐based membranes exhibit extremely high water permeation (45.9 L/m2·h·bar) without losing their salt rejection ability. The nanofiltration performances of these polyamide‐based membranes are higher than most of the reported nanofiltration membranes in recent years. [ABSTRACT FROM AUTHOR]

Organic solvent nanofiltration (OSN) membranes have become a powerful separation platform in a myriad of chemical and pharmaceutical fields owing to their superior merits in high separation efficiency and low energy consuming. Despite extensive progress in exploiting polyamide thin film composite (TFC) membranes for OSN, they are heavily limited by inferior solvent permeability, especially when using conventional low-porous polyimide as TFC substrate. Herein, we report a facile substrate engineering strategy to leverage macro-porous Nylon66 microfiltration membrane to replace the conventional low-porous polyimide substrates for fabricating TFC membranes by interfacial polymerization, enabling high and robust solvent permeability during OSN. Distinct from conventional polyimide, Nylon66 substrates take advantage of their high porosity, macro-porous size and excellent hydrophilicity to realize more monomers storage and uniform monomers distribution, allowing to create crumpled and defect-free polyamide layers. With this method, the polyamide TFC membranes show a 2.1-fold increase in ethanol permeance (up to 16.0 L h−1 m−2 bar−1) meanwhile possessing 98 % rejection of dye, surpassing the most reported TFC membranes. We also demonstrate that the TFC membranes exhibit excellent long-term stability in both polar and non-polar solvent, as well as hold huge promise in the precise separation of dye mixture, pharmaceutical ingredient, and catalyst. [Display omitted] • Nylon 66 substrate is first used to prepare TFC-based organic solvent nanofiltration membranes. • TFC membranes using Nylon 66 substrate feature crumpled and defect-free polyamide layer. • TFC membranes show an ultrahigh ethanol permeance of 16.0 L h−1 m−2 bar−1 and 98 % dye rejection. • TFC membranes deliver stable precise screening ability in both polar and non-polar solvent. [ABSTRACT FROM AUTHOR]

High-performance polyamide thin film composite (TFC) nanofiltration membranes have received great attention in recent years. Herein, we report the preparation of TFC nanofiltration membranes by interfacial polymerization using MoS 2 nanosheets as the nanomaterial interlayer. The aqueous monomer and MoS 2 nanosheets are distributed on the surface of microporous membrane substrates by a one-step method. The MoS 2 interlayer improves the uniformity and smoothness of the microporous substrates, helping to form polyamide nanofilms at ultralow monomer concentration. Moreover, the hydrophilic and negatively-charged MoS 2 nanosheets enhance the water permeability and negative charges of the nanofiltration membranes. The composite membranes show both high water permeance of 33.5 L m−2 h−1 bar−1 and Na 2 SO 4 rejection of 97.5%, as well as significantly improved mono-/divalent anions selectivity and antifouling property. It is proved that the interfacial polymerization strategy assisted by the MoS 2 interlayer is effective for preparing high-performance nanofiltration membranes. [Display omitted] • Nanofiltration membranes with MoS 2 nanosheet interlayer are fabricated. • MoS 2 interlayer provides an even platform for interfacial polymerization. • The nanofiltration membrane shows a water permeance of 33.5 L m-2 h-1 bar-1 and a rejection of 97.5% for Na 2 SO 4. • The nanofiltration membrane exhibits excellent long-term stability and antifouling ability. [ABSTRACT FROM AUTHOR]

Porous substrates act as open "interfacial reactors" during the synthesis of polyamide composite membranes via interfacial polymerization. However, achieving a thin and dense polyamide nanofilm with high permeance and selectivity is challenging when using a conventional substrate with uniform wettability. To overcome this limitation, we propose the use of Janus porous substrates as confined interfacial reactors to decouple the local monomer concentration from the total monomer amount during interfacial polymerization. By manipulating the location of the hydrophilic/hydrophobic interface in a Janus porous substrate, we can precisely control the monomer solution confined within the hydrophilic layer without compromising its concentration. The hydrophilic surface ensures the uniform distribution of monomers, preventing the formation of defects. By employing Janus substrates fabricated through single-sided deposition of polydopamine/polyethyleneimine, we significantly reduce the thickness of the polyamide nanofilms from 88.4 to 3.8 nm by decreasing the thickness of the hydrophilic layer. This reduction leads to a remarkable enhancement in water permeance from 7.2 to 52.0 l/m 2 ·h·bar while still maintaining ~96% Na 2 SO 4 rejection. The overall performance of this membrane surpasses that of most reported membranes, including state-of-the-art commercial products. The presented strategy is both simple and effective, bringing ultrapermeable polyamide nanofilms one step closer to practical separation applications., Competing Interests: Competing interests: The authors declare that they have no competing interests., (Copyright © 2024 Cheng-Ye Zhu et al.)