Graphene Oxide Nanocolloids

Luo, Jiayan; Cote, Laura J.; Tung, Vincent; Tan, Alvin T. L.; Goins, Philip E.; Wu, Jinsong; Huang, Jiaxing

doi:10.1021/ja1078943

Cited by 362 publications

(331 citation statements)

References 34 publications

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“…GO membranes with different IL spacing were prepared by storing them in a sealed container with different RH of 0%, 12%, 33%, 75%, 84% and 100%. To this end, we used saturated solutions of LiCl (12% RH), MgCl 2 (33%), NaCl (75%) and KCl (84%), which were prepared by dissolving excess amounts of salts in deionised water 30,36 . A humidity meter was used inside the container to check that the salts provided the literature values of RH.…”

Section: Methodsmentioning

confidence: 99%

“…Graphene oxide (GO) has previously been suggested as a 2D-surfactant to prepare stable dispersions of graphite and carbon nanotubes (CNTs) in water 29,30 . Here, graphene oxidegraphene (GO-Gr) aqueous dispersions were prepared by exfoliating graphite in water using GO as a surfactant.…”

Section: Swelling-controlled Graphene Oxide-graphene (Go-gr)membranesmentioning

confidence: 99%

“…The laminates were cut into rectangular strips (4 mm × 10 mm) and stored for one to two weeks at different relative humidities (RH), achieved using saturated salt solutions 18,30 . The resulting interlayer spacing was measured by X-ray diffraction as shown in Fig.…”

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confidence: 99%

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Tunable sieving of ions using graphene oxide membranes

et al. 2017

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Graphene oxide membranes show exceptional molecular permeation properties, with a promise for many applications. However, their use in ion sieving and desalination technologies is limited by a permeation cutoff of 9 Å, which is larger than hydrated ion diameters for common salts. The cutoff is determined by the interlayer spacing d 13.5 Å, typical for graphene oxide laminates that swell in water. Achieving smaller d for the laminates immersed in water has proved to be a challenge. Here we describe how to control d by physical confinement and achieve accurate and tuneable ion sieving. Membranes with d from  9.8 Å to 6.4 Å are demonstrated, providing the sieve size smaller than typical ions' hydrated diameters. In this regime, ion permeation is found to be thermally activated with energy barriers of 10-100 kJ/mol depending on d. Importantly, permeation rates decrease exponentially with decreasing the sieve size but water transport is weakly affected (by a factor of <2). The latter is attributed to a low barrier for water molecules entry and large slip lengths inside graphene capillaries. Building on these findings, we demonstrate a simple scalable method to obtain graphene-based membranes with limited swelling, which exhibit 97% rejection for NaCl.Selectively permeable membranes with sub-nm pores attract strong interest due to analogies with biological membranes and potential applications in water filtration, molecular separation and desalination [1][2][3][4][5][6][7][8] . Nanopores with sizes comparable to, or smaller than, the diameter D of hydrated ions are predicted to show enhanced ion selectivity 7,9-12 because of dehydration required to pass through such atomic-scale sieves. Despite extensive research on ion dehydration effects 3,7,9-13 , experimental investigation of the ion sieving controlled by dehydration has been limited because of difficulties in fabricating uniform membranes with well-defined sub-nm pores. The realisation of membranes with dehydration-assisted selectivity would be a significant step forward. So far, research into novel membranes has mostly focused on improving the water flux rather than ion selectivity. On the other hand, modelling of practically relevant filtration processes shows that an increase in water permeation rates above the rates currently achieved (2-3 L/m 2 ×h×bar) would not contribute greatly to the overall efficiency of desalination 8,14,15 . Alternative approaches based on higher water-ion selectivity may open new possibilities for improving filtration technologies, as the performance of state-of-the-art membranes is currently limited by the solution-diffusion mechanism, in which water molecules dissolve in the membrane material and then diffuses across the membrane 8 . Recently, carbon nanomaterials including carbon nanotubes (CNT)

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Section: Methodsmentioning

confidence: 99%

Section: Swelling-controlled Graphene Oxide-graphene (Go-gr)membranesmentioning

confidence: 99%

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Tunable sieving of ions using graphene oxide membranes

et al. 2017

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“…Therefore, control of graphite oxidation is necessary for various applications of graphene oxide sheets. It was recently reported that graphene oxide sheets with different oxygen content amounts can be prepared simply by changing the starting graphite, oxidation time, and amount of oxidant, providing variation in the size distribution, electrical conductivity, and energy band gap [21][22][23][24]. However, no correlation between the properties or size of graphene oxide sheets and the oxidation temperature has been reported thus far.…”

Section: Degree Of Oxidation Of Graphitementioning

confidence: 99%

Control of size and physical properties of graphene oxide by changing the oxidation temperature

Kang¹,

Shin²

2012

Carbon letters

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The size and the physical properties of graphene oxide sheets were controlled by changing the oxidation temperature of graphite. Graphite oxide (GO) samples were prepared at different oxidation temperatures of 20 This indicates that the C/O ratio and the average size of the graphene oxide sheets respectively increase as the oxidation temperature decreases. Moreover, it was observed that the surface charge and optical properties of the graphene oxide sheets could be tuned by changing the temperature. This study demonstrates the tunability of the physical properties of graphene oxide sheets and shows that the properties depend on the functional groups generated during the oxidation process.

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“…72 These structures are 2-3 nm in diameter, have two or three p-stacked PAH moieties comprising the core, and an oxygen-rich corona. 73 The optical properties of these structures are highly dependent on particle size; the absorption maxima red-shifts with increased particle size, while emission wavelength depends on the excitation energy, possibly due to variation in the density of defect sites associated with sp 2 carbons.…”

Section: Nanoscale Assembly T Emrick and E Pentzermentioning

confidence: 99%

Nanoscale assembly into extended and continuous structures and hybrid materials

Emrick

Pentzer

2013

NPG Asia Mater

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Harnessing synthetic power to create novel materials with unique assembly properties is of fundamental interest for pushing the limits of molecular and macromolecular assembly, while further holding the potential for improving electronic and medical device performance. Controlling the assembly of aromatic molecules into nanostructures provides routes towards continuous and extended structures with performance that is improved markedly over that of their individual molecular components, opening possibilities for the formation of composites that have tailored interactions with other materials and thus improved applications. This review covers recent advances in the synthesis of conjugated materials, their controlled assembly into nanoscale architectures and implementation into devices. Specifically, we discuss the solution-based assembly of polythiophene into nanowire fibrils, the formation of columnar stacks of hexabenzocoronene liquid crystals and the preparation of functionalized solution processible graphene for nanocomposite formation.

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Graphene Oxide Nanocolloids

Cited by 362 publications

References 34 publications

Tunable sieving of ions using graphene oxide membranes

Tunable sieving of ions using graphene oxide membranes

Control of size and physical properties of graphene oxide by changing the oxidation temperature

Nanoscale assembly into extended and continuous structures and hybrid materials

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