Composite hydrogel-loaded alumina membranes for nanofluidic molecular filtration

Wu, Songmei; Braschler, Thomas; Anker, Rebekka; Wildhaber, Fabien; Bertsch, Arnaud; Brugger, Jürgen; Renaud, Philippe

doi:10.1016/j.memsci.2014.12.023

Cited by 15 publications

(18 citation statements)

References 41 publications

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“…For this, we synthesized covalently crosslinked alginate hydrogels by wellestablished carbodiimide chemistry 24,25 , with water-soluble 65 carbodiimide (EDC) as the activator, and the di-amine adipic dihydrazide as the crosslinker (Fig. 1A).…”

Section: Resultsmentioning

confidence: 99%

“…Adipic acid dihydrazide is used to provide covalent crosslinks between carboxyl groups of the alginate chain. To do so, the carboxylgroups are activated by a carbodiimide (EDC), followed by condensation with the amino groups of the adipic acid dihydrazide 24,25 . B) Ionic partition.…”

Section: Theorymentioning

confidence: 99%

“…We are mostly interested in the partition of negatively charged co-ion probes in the gel. 25 The inhomogeneous distribution of the space charge for the solid nanochannel and soft hydrogel model (eq. 6-B respectively 6-C) requires numerical integration of equations 1 and 2 to obtain a numerical solution for Φ(x) for the fixed charge densities specified by equation 5 in conjunction with 6-B or 6-C. On the 30 other hand, under the Gibbs-Donnan approximation (equation 6-A), the solution is particularly simple 14 :…”

Section: Theorymentioning

confidence: 99%

“…7 When allowing for partial polymer strand mobility, a larger effective volume fraction is occupied by the fixed space charge, we refer to this case as « soft hydrogel model. » 25 We further investigate the partitioning of a macromolecular, highly negatively charged probe into the covalent alginate gels, in order to better understand the relationship between ionic exclusion effects for macromolecules versus small molecules. Indeed, while electrostatic interaction is considered to be of prime 30 importance of small molecules, the pore size distribution according to the Ogston model 5 is reported to be of main importance for the partitioning of macromolecules into hydrogels, including charged gels.…”

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confidence: 99%

“…For the solid nanochannel simulations, the fixed space charge is assumed to be concentrated in periodic patches occupying 5% of the available space, and is assumed to have a local concentration of 5M negative residues; overall, this gives to a mean space charge of 250mM=-0.24C/m 3 . The structure was assumed to be at A second theoretical issue arising with highly charged 25 macromolecules is Manning counter-ion condensation and shielding by the mobile charges 13 , both effects leading to lowering of the effective electrostatic repulsion. By explicit calculation of the electrostatic repulsion energy in the PoissonBoltzmann framework 13,21 , we take these effects into account; we 30 calculate an effective charge density that lies in the range of 10%-30% of the nominal charge density for the relevant experimental conditions (Details are given in Electronic Supplementary Information 1).…”

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confidence: 99%

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Soft nanofluidics governing minority ion exclusion in charged hydrogels

Braschler

Wildhaber

et al. 2015

Soft Matter

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We investigate ionic partition of negatively charged molecular probes into also negatively charged, covalently crosslinked alginate hydrogels. The aim is to delimit the domain of validity of the major 15 nanoelectrostatic models, and in particular to assess the influence of hydrogel chain mobility on ionic partition. We find that the widely used Gibbs-Donnan model greatly overestimates exclusion of the co-ion probes used. For low molecular weight probes, a much better fit is obtained by taking into account the electrostatics in the nanometric gel pores by means of the Poisson-Boltzmann framework; the fit is improved slightly when taking into account alginate chain mobility. For high molecular weight probes, 20 we find it essential to take into account local gel deformation due to electrostatic repulsion between the flexible gel strands and the probe. This is achieved by combining Poisson-Boltzmann simulations with heterogeneous pore size distribution given by the Ogston model, or more simply and precisely, by applying a semi-empirical scaling law involving the ratio between Debye length and pore size.

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Section: Resultsmentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Soft nanofluidics governing minority ion exclusion in charged hydrogels

Braschler

Wildhaber

et al. 2015

Soft Matter

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Green Synthesis of Low‐Dimensional Aluminum Oxide Hydroxide and Oxide Using Liquid Metal Reaction Media: Ultrahigh Flux Membranes

Zavabeti

Zhang

Castro

et al. 2018

Adv Funct Materials

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Liquid metal reaction media provides exciting new avenues for synthesizing low-dimensional materials. Here, the synthesis of atomically thin sheets and nanofibers of boehmite (γ-AlOOH) and their transformation into cubic alumina (γ-Al 2 O 3 ) via annealing is explored. The sheets are as thin as one orthorhombic boehmite unit cell. The addition of aluminum into a room temperature alloy of gallium, followed by exposing the melt to either liquid water or water vapor, allows growing either 2D sheets or 1D fibers, respectively. The isolated oxide hydroxides feature large surface areas, with the sheet morphologies also showing a high Young's modulus. The method is green, since the liquid metal solvent can be fully reused. The ultrathin boehmite sheets are found suitable for the development of freestanding membrane filters that enable excellent separation of heavy metal ions and oil from aqueous solutions at extraordinary filtrate flux. The developed liquid metal-based synthesis process offers a sustainable, green, and rapid method for synthesizing nanomorphologies of metal oxides which are challenging to obtain by conventional methods. The process is both sustainable and scalable and may be explored for the creation of other types of metal oxide compounds.

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Designing Semipermeable Hydrogel Shells with Controlled Thickness through Internal Osmosis in Triple‐Emulsion Droplets

Lee

Che

Tai

et al. 2021

Adv Funct Materials

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Hydrogel shells that compartmentalize the water core from the aqueous surrounding provide molecular selectivity on size and charge in transmembrane transport. It is highly demanding to produce thin hydrogel shells to minimize diffusion length and maximize core volume. Here, internal osmosis in water-in-oil-in-water-in-oil (W/O/W/O) triple-emulsion droplets is used to produce thin hydrogel shells enclosing a large water core. The triple-emulsion droplets are prepared to have an ultrathin middle oil layer using a capillary microfluidic device. The innermost water droplet has a higher osmolarity than the outer water layer containing photopolymerizable hydrogel precursors, which pumps water from the outer layer to the core through the ultrathin oil layer by the osmosis. Therefore, the outer layer gets thinner and hydrogel precursors are enriched while the size of the triple-emulsion droplets remains unchanged. Through photopolymerization of precursors and phase transfer from oil to water, hydrogel shells enclosing water core are produced in the water environment; the oil layer is ruptured for molecular exchange through the shells. The thickness and composition of the hydrogel shells are precisely controllable by the osmotic conditions. The shells show a high permeation rate due to the thinness as well as controlled cut-off threshold of permeation for neutral and charged molecules.

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Composite hydrogel-loaded alumina membranes for nanofluidic molecular filtration

Cited by 15 publications

References 41 publications

Soft nanofluidics governing minority ion exclusion in charged hydrogels

Soft nanofluidics governing minority ion exclusion in charged hydrogels

Green Synthesis of Low‐Dimensional Aluminum Oxide Hydroxide and Oxide Using Liquid Metal Reaction Media: Ultrahigh Flux Membranes

Designing Semipermeable Hydrogel Shells with Controlled Thickness through Internal Osmosis in Triple‐Emulsion Droplets

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