Gas transfer in supported films made by molecular self-assembly of ionic polymers

Stroeve, Pieter; Vásquez, Victor R.; Coelho, Manuel A. N.; Rabolt, John F.

doi:10.1016/s0040-6090(95)08428-2

Cited by 117 publications

(94 citation statements)

References 7 publications

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“…The possibility to deposit ESA-films to a limited extent on untreated PMMA, poly(phenylene oxide), or poly(etherimide)s 54) , too, or on formvar 272,288) points to the second explanation. As expected, supports made of untreated unpolar polymers however, such as polyolefins or poly(tetrafluoroethylene), give poor results only 26,54,99,141,253,311,402) . Basically, surface modification may provide charges to any substrate, not only to organic polymers, to render it useful for ESA.…”

Section: Useful Substratessupporting

confidence: 75%

“…Other geometries, such as fibers, seem to pose no particular problems 405,413) . Porous materials have been used, too, but a substantial number of dipping cycles was needed to cover the pores efficiently 99,402,405,414) . It is not known to which extent and how far the polyions may even penetrate into the pores to build-up multilayer coatings inside of membranes 415,416) .…”

Section: Useful Substratesmentioning

confidence: 99%

“…28). Also, when deposited on porous supports, high pressures can produce cracks in the coating 402) .…”

Section: Quality and Stability Of Esa-filmsmentioning

confidence: 99%

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Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials, structure and properties

Bertrand

Jonas

Laschewsky³

et al. 2000

Macromol. Rapid Commun.

1,173

1,184

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A bit of historyThe key role of surfaces for many material properties as well as for many biological processes has been recognized now. Therefore, new strategies aim at the tailoring of the material's surface only -or of a thin surface layer, respectively -, while preserving the bulk properties of the underlying support. Particular emphasis has been given to the surface modification by polymers, in an attempt to extend the known versatility of polymer bulk materials to ultrathin films and coatings, and to prepare bulk-surface composite materials. The self-organization of polymers has been increasingly explored for the preparation of well-defined surfaces and interfaces in recent years, extending the use of the established methods of low molar mass compounds (for comparative reviews, see ref. 1-3)). With such techniques, polymer films are formed spontaneously on substrates, due to balanced interactions between substrate, polymer (or its precursor) and medium. Typically, very thin, often monomolecular layers are produced. Repetitive deposition steps provide a precise control over the total thickness of the coatings, in the range from a few angstroms up to the micrometer range. Moreover, the step-by-step procedures allow for a fine structuring in the third dimension. In addition to the preparation of uniform and homogeneous coatings, gratings, gradients or steps of defined height in molecular dimensions can be easily constructed.The most recent of the self-organization techniques is the alternating physisorption of oppositely charged polyelectrolytes, the so-called "layer-by-layer" method or "electrostatic self-assembly" (ESA) [3][4][5][6][7][8][9][10] . Although some early, singular studies of self-assembly by alternating adsorption of oppositely charged polyions are reported [11][12][13] , a practical method for ESA was developed Feature Article: The article presents the state-of-the-art of alternating physisorption of oppositely charged polyelectrolytes, the so-called "layer-by-layer" method or "electrostatic self-assembly" (ESA), for the preparation of thin polymer coatings. In comparison to other, more established self-organization techniques, this recent method is distinguished by its simplicity, versatility, and speed. In particular, the tendency for self-healing is unique. Emphasis is given to the role of the molecular structure of the polyelectrolytes, and to the nature of the support. Also, various parameters for the preparation of multilayer films are highlighted, which are very important due to the kinetic control of the build-up process. The structure of the resulting coatings, their quality and stability, chemical reactions in the films, and potential applications are discussed.Macromol. Rapid Commun. 21, No. 7

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Section: Useful Substratessupporting

confidence: 75%

Section: Useful Substratesmentioning

confidence: 99%

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Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials, structure and properties

Bertrand

Jonas

Laschewsky³

et al. 2000

Macromol. Rapid Commun.

1,173

1,184

View full text Add to dashboard Cite

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“…20,21 Through theoretical modeling, these authors demonstrated a dependence of the apparent transfer rate and charge distribution of monovalent ions on polyelectrolyte multilayers at such modified interfaces. Those multilayers were also more permeable to monovalent ions than multivalent ions, and the permeability of highly charged ions such as Fe(CN) 6 3− and Ru(NH 3 ) 6 3+ will decrease quickly when polyelectrolyte multilayers are assembled. 22 The slower diffusion with increased number of multilayer is attributed to the reduction of active area of charge transfer, and the active area may be merely a few spots on the film surface that are preferable to the transport of ions.…”

mentioning

confidence: 99%

Kinetic Modulation of Pulsed Chronopotentiometric Polymeric Membrane Ion Sensors by Polyelectrolyte Multilayers

Shvarev

et al. 2007

Anal. Chem.

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Polymeric membrane ion selective electrodes are normally interrogated by zero current potentiometry, and their selectivity is understood to be primarily dependent on an extraction/ionexchange equilibrium between the aqueous sample and polymeric membrane. If concentration gradients in the contacting diffusion layers are insubstantial, the membrane response is thought to be rather independent of kinetic processes such as surface blocking effects. In this work, the surface of calcium-selective polymeric ion-selective electrodes is coated with polyelectrolyte multilayers as evidenced by zeta potential measurements, atomic force microscopy and electrochemical impedance spectroscopy. Indeed, such multilayers have no effect on their potentiometric response if the membranes are formulated in a traditional manner, containing a lipophilic ion-exchanger and a calcium-selective ionophore. However, drastic changes in the potential response are observed if the membranes are operated in a recently introduced kinetic mode using pulsed chronopotentiometry. The results suggest that the assembled nanostructured multilayers drastically alter the kinetics of ion transport to the sensing membrane, making use of the effect that polyelectrolyte multilayers have different permeabilities toward ions with different valences. The results have implications to the design of chemically selective ion sensors since surface localized kinetic limitations can now be used as an additional dimension to tune the operational ion selectivity.Polymer membrane ion-selective electrodes are widely established for the reliable assessment of ion activities in complex samples and are indispensable tools in clinical analysis. Their ionselectivity is dictated by the thermodynamic ion-exchange selectivity of the polymer membrane. Recently, ion-selective membrane electrodes have started to be interrogated by pulsed chronopotentiometry. In this new technique, a discrete current pulse is imposed across an ion-selective membrane void of added ion-exchanger sites. The potential change associated with the resulting ion flux from the sample into the sensing phase can be monitored during or, at open circuit, immediately after the pulse before the membrane is regenerated under controlled potential conditions. At high sample concentrations the observed sensitivity (electrode slope) and selectivity normally agrees with that of the corresponding ion-selective electrodes interrogated at zero current. 1, 2 The imposed ion flux, however, depletes the analyte ions in the Nernst diffusion layer at a critical concentration, and very large (ca. 10-fold Nernstian) electrode slopes are observed in this concentration range. 3 The operational ion Ultra-thin films assembled from alternate adsorption of polycations and polyanions onto a charged substrate has attracted much attention in recent years due to their facile fabrication, high versatility and multi-functionality. The application of this technique has expanded into a number of areas, including biosensor surface modificat...

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“…The construction of separation and purification membranes for ions and molecules has also been studied using LbL films and related systems [29][30][31][32]. LbL films composed of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS), which were deposited on the surface of porous supports (pore diameter 20-200 nm), exhibited a high flux of monovalent ions while the flux of multivalent ions was significantly suppressed as a result of enhanced Donnan exclusion, as well as hindered diffusion in the film [33][34][35].…”

Section: Open Accessmentioning

confidence: 99%

Ion Permeability of Free-Suspended Layer-by-Layer (LbL) Films Prepared Using an Alginate Scaffold

2013

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Abstract:Layer-by-layer (LbL) films were prepared over an aperture (diameter 1-5 mm) on a glass plate to study ion permeation across free-suspended LbL films. LbL films were prepared by depositing alternating layers of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) on the surface of a glass plate with an aperture filled with an alginate gel, followed by dissolution of the alginate gel. PAH-PSS films prepared in this way showed permeability to inorganic salts, depending on the size and charge. Permeability to alkali metal chlorides depended on the Stokes radius of the alkali metal cations. The effect of the type of halide was negligible because of the halides' smaller ionic radii. Permeation of multivalent ions such as Ru(NH 3 ) 6 3+ and [Fe(CN) 6 ] 3− was severely suppressed owing to Donnan exclusion.

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Gas transfer in supported films made by molecular self-assembly of ionic polymers

Cited by 117 publications

References 7 publications

Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials, structure and properties

Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials, structure and properties

Kinetic Modulation of Pulsed Chronopotentiometric Polymeric Membrane Ion Sensors by Polyelectrolyte Multilayers

Ion Permeability of Free-Suspended Layer-by-Layer (LbL) Films Prepared Using an Alginate Scaffold

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