Fabrication of soft-etched nanoporous polyimide membranes for ionic conduction and discrimination

Froehlich, Kristina; Nasir, Saima; Ali, Mubarak; Ramı́rez, Patricio; Cervera, Javier; Mafé, Salvador; Ensinger, Wolfgang

doi:10.1016/j.memsci.2020.118633

Cited by 21 publications

(19 citation statements)

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“…Current−Voltage (I−V) Curves: For the measurement of electrical readout, the DMF-treated membrane sample was mounted between the two compartments of a home-made electrochemical cell. [15,46] The effective membrane area in contact with the electrolyte solution was ≈8 mm 2 . The electrolytes containing various crown-ether concentrations were prepared in aqueous alkali chloride (100 × 10 -3 m) solutions.…”

Section: Methodsmentioning

confidence: 99%

“…For this purpose, the Ag|AgCl electrodes were dipped in the electrolyte solution on both sides of membrane sample to control the input potentials and output currents in a triangular wave signal. [15,46]…”

Section: Methodsmentioning

confidence: 99%

“…Finally, the DMF‐treated samples were thoroughly washed with distilled water before electrical measurements. Additional details can be found elsewhere [ 46 ] where the authors considered the transport of alkali and small organic cations only.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we have developed a soft‐etch technique to obtain nanochannels in polyimide (PI) membranes irradiated with heavy ions. [ 46 ] PI exhibits high chemical, electrical, and heat resistance. Therefore, the chemical etching of ion tracks in PI membranes requires harsh conditions.…”

Section: Introductionmentioning

confidence: 99%

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Size‐Based Cationic Molecular Sieving through Solid‐State Nanochannels

Ali

Nasir

Froehlich

et al. 2021

Adv Materials Inter

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filled with electrolyte solutions and the transport of molecules or ions through the pores provides the relevant information required for each particular application. This transport is regulated by the channel size and the physico-chemical characteristics of the channel surface. In biological membranes, the high selectivity and fast ion transport achieved are also ascribed to the precise channel size and functional groups distributed along the channel surface. [24-26] A wide range of experimental techniques are available to tune the channel diameter and surface chemistry to enhance ionic selectivity. They include the preparation of hybrid biological/artificial solid-state membranes, [27,28] channel size tuning through electroless [12,29,30] and atomic layer [31-33] depositions, the grafting of polymer brushes on the channel surface, [34-38] and the deposition of an atomically thin graphene layer on the porous membrane. [39,40] Molecular filtration and discrimination have been achieved using different membranes. For example, Martin and co-workers have employed gold-coated nanochannels for the separation of organic molecules and drug enantiomers based on their charge or molecular size. [12,29,30] Stroeve et al. have demonstrated the pH-responsive transport of ions and biomolecules [41] and Savariar et al. the molecular size-, charge-, and hydrophobicity-based discrimination of organic molecules and proteins [14] using modified nanoporous membranes. Recently, polymer membranes with subnanometer pores have been obtained without specific chemical treatments. For example, track-UV techniques have been employed to fabricate subnanopores which exhibited highly selective and ultrafast ion sieving behavior. [42,43] Moreover, subnanometer pores in metal-organic frameworks integrated inside the bullet-shaped nanochannels of a polymer membrane also exhibited high selectivity towards alkali cations while rejecting divalent ions. [44,45] Recently, we have developed a soft-etch technique to obtain nanochannels in polyimide (PI) membranes irradiated with heavy ions. [46] PI exhibits high chemical, electrical, and heat resistance. Therefore, the chemical etching of ion tracks in PI membranes requires harsh conditions. Usually, the ion tracks in PI are etched with a strong inorganic etchant (chlorine in hypochlorite) at high temperature. Contrary to chemical etching, in a soft-etching technique, the ion tracked PI membranes are exposed to an organic solvent which selectively dissolves the damage trails (latent tracks) caused by the energetic The molecular sieving behavior of soft-etched polyimide membranes having negatively charged nanochannels is described experimentally and theoretically using alkali metal-crown ether cationic complexes and alkylammonium cations. To this end, the electrical conduction and current rectification obtained with different alkali electrolyte solutions (LiCl, NaCl, and KCl) and crown ether molecules (12-crown-4, 15-crown-5, and 18-crown-6) are studied. The results suggest that only the [Li(12C4)] + comp...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Size‐Based Cationic Molecular Sieving through Solid‐State Nanochannels

Ali

Nasir

Froehlich

et al. 2021

Adv Materials Inter

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“…The constructed ionic gates enabled selective cation and anion conduction through the nanochannel, exhibiting great potentials in clinical medicine, biosensors and drug delivery (Figure b). Most recently, Ensinger’s group reported an alkali metal cation-selective nanopores based on heavy ion-tracked PI membranes via the soft-etching (SE) technique, which selectively dissolved the latent ion tracks in the membranes by an organic solvent to form tiny pores . The SE-PI nanoporous membranes could efficiently discriminate alkali cations from divalent metal cations and ammonium cations from tetraalkylammonium cations.…”

Section: Polymeric Nanochannel-based Biosensing Platforms For Detecti...mentioning

confidence: 99%

Bio-inspired Track-Etched Polymeric Nanochannels: Steady-State Biosensors for Detection of Analytes

2021

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Bio-inspired polymeric nanochannel (also referred as nanopore)-based biosensors have attracted considerable attention on account of their controllable channel size and shape, multi-functional surface chemistry, unique ionic transport properties, and good robustness for applications. There are already very informative reviews on the latest developments in solid-state artificial nanochannel-based biosensors, however, which concentrated on the resistive-pulse sensing-based sensors for practical applications. The steady-state sensing-based nanochannel biosensors, in principle, have significant advantages over their counterparts in term of high sensitivity, fast response, target analytes with no size limit, and extensive suitable range. Furthermore, among the diverse materials, nanochannels based on polymeric materials perform outstandingly, due to flexible fabrication and wide application. This compressive Review summarizes the recent advances in bio-inspired polymeric nanochannels as sensing platforms for detection of important analytes in living organisms, to meet the high demand for high-performance biosensors for analysis of target analytes, and the potential for development of smart sensing devices. In the future, research efforts can be focused on transport mechanisms in the field of steady-state or resistive-pulse nanochannel-based sensors and on developing precisely size-controlled, robust, miniature and reusable, multi-functional, and high-throughput biosensors for practical applications. Future efforts should aim at a deeper understanding of the principles at the molecular level and incorporating these diverse pore architectures into homogeneous and defect-free multi-channel membrane systems. With the rapid advancement of nanoscience and biotechnology, we believe that many more achievements in nanochannel-based biosensors could be achieved in the near future, serving people in a better way.

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Bioinspired Solid‐State Nanochannel Sensors: From Ionic Current Signals, Current, and Fluorescence Dual Signals to Faraday Current Signals

Zhang¹,

Zhang²

2021

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Inspired from bioprotein channels of living organisms, constructing “abiotic” analogues, solid‐state nanochannels, to achieve “smart” sensing towards various targets, is highly seductive. When encountered with certain stimuli, dynamic switch of terminal modified probes in terms of surface charge, conformation, fluorescence property, electric potential as well as wettability can be monitored via transmembrane ionic current, fluorescence intensity, faraday current signals of nanochannels and so on. Herein, the modification methodologies of nanochannels and targets‐detecting application are summarized in ions, small molecules, as well as biomolecules, and systematically reviewed are the nanochannel‐based detection means including 1) by transmembrane current signals; 2) by the coordination of current‐ and fluorescence‐dual signals; 3) by faraday current signals from nanochannel‐based electrode. The coordination of current and fluorescence dual signals offers great benefits for synchronous temporal and spatial monitoring. Faraday signals enable the nanoelectrode to monitor both redox and non‐redox components. Notably, by incorporation with confined effect of tip region of a needle‐like nanopipette, glorious in‐vivo monitoring is conferred on the nanopipette detector at high temporal‐spatial resolution. In addition, some outlooks for future application in reliable practical samples analysis and leading research endeavors in the related fantastic fields are provided.

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Fabrication of soft-etched nanoporous polyimide membranes for ionic conduction and discrimination

Cited by 21 publications

References 52 publications

Size‐Based Cationic Molecular Sieving through Solid‐State Nanochannels

Size‐Based Cationic Molecular Sieving through Solid‐State Nanochannels

Bio-inspired Track-Etched Polymeric Nanochannels: Steady-State Biosensors for Detection of Analytes

Bioinspired Solid‐State Nanochannel Sensors: From Ionic Current Signals, Current, and Fluorescence Dual Signals to Faraday Current Signals

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