Crumpled Nanopaper from Graphene Oxide

Ma, Xiaofei; Zachariah, Michael R.; Zangmeister, Christopher D.

doi:10.1021/nl203964z

Cited by 165 publications

(214 citation statements)

References 16 publications

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“…Despite interesting theoretical progress [70,71], the existence of a crumpled phase with self-avoidance remains unclear at the present time [32,40]. We note that crumpled objects with fractional dimensions can be obtained experimentally by rapidly evaporating a solution containing graphene oxide membranes [72]. Remarkably, the measured fractal dimension D f ≈ 2.5-2.7 is in good agreement with the Flory-type argument, but one should note that such balls may be out of equilibrium and dominated by sticky van der Waals attractions.…”

Section: Introductionmentioning

confidence: 93%

Statistical Mechanics of Thin Spherical Shells

Košmrlj

Nelson

2017

Phys. Rev. X

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We explore how thermal fluctuations affect the mechanics of thin amorphous spherical shells. In flat membranes with a shear modulus, thermal fluctuations increase the bending rigidity and reduce the inplane elastic moduli in a scale-dependent fashion. This is still true for spherical shells. However, the additional coupling between the shell curvature, the local in-plane stretching modes, and the local out-ofplane undulations leads to novel phenomena. In spherical shells, thermal fluctuations produce a radiusdependent negative effective surface tension, equivalent to applying an inward external pressure. By adapting renormalization group calculations to allow for a spherical background curvature, we show that while small spherical shells are stable, sufficiently large shells are crushed by this thermally generated "pressure." Such shells can be stabilized by an outward osmotic pressure, but the effective shell size grows nonlinearly with increasing outward pressure, with the same universal power-law exponent that characterizes the response of fluctuating flat membranes to a uniform tension.

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Section: Introductionmentioning

confidence: 93%

Statistical Mechanics of Thin Spherical Shells

Košmrlj

Nelson

2017

Phys. Rev. X

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“…For example, submicrometer-size ball-like crumpled graphene structures can be produced by isotropic compression and thermal reduction of GO [202]. Ma et al [203] also reported the fabrication of few hundred nanometer-size crumped graphene ball by rapid drying of GO. Unlike wrinkled graphene that experiences deformation by uniaxial confining forces, crumpled graphene undergoes multidirectional compression.…”

Section: Disorders In Graphene Structurementioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

533

187

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Monolayer graphene exhibits extraordinary properties owing to the unique, regular arrangement of atoms in it. However, graphene is usually modified for specific applications, which introduces disorder. This article presents details of graphene structure, including sp2 hybridization, critical parameters of the unit cell, formation of σ and π bonds, electronic band structure, edge orientations, and the number and stacking order of graphene layers. We also discuss topics related to the creation and configuration of disorders in graphene, such as corrugations, topological defects, vacancies, adatoms and sp3-defects. The effects of these disorders on the electrical, thermal, chemical and mechanical properties of graphene are analyzed subsequently. Finally, we review previous work on the modulation of structural defects in graphene for specific applications.

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“…GO exhibits a rough surface showing wrinkles 41,42 . It has been reported that during the drying process of GO, water exerts surface tension due to high affinity to GO oxidized domains 43 , inducing stresses during evaporation 44 , which force the soft sheets to fold and wrinkle 45,46 and/or can exacerbate the wrinkled structure 43 . In particular, in Figures 1E and 1F nanosheets edges of about 5 nm can be detected that correspond to the largest thickness observed in the sample.…”

Section: Go Characterizationmentioning

confidence: 99%

Formation of Cellulose Acetate–Graphene Oxide Nanocomposites by Supercritical CO₂ Assisted Phase Inversion

Baldino

Sarno

Cardea

et al. 2015

Ind. Eng. Chem. Res.

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(Stefano Cardea) Phone Number: +39089969365; msarno@unisa.it (Maria Sarno) Phone Number: +39089964057.KEYWORDS: Graphene oxide, Cellulose acetate, Nanocomposite, Supercritical CO 2 . ABSTRACTCellulose acetate (CA)/graphene oxide (GO) nanocomposite membranes were generated by an assisted phase inversion process, based on the use of SC-CO 2 as non-solvent, operating at 200 bar and 40 °C; loadings of GO up to 9% w/w were tested. The structures maintained the cellular morphology, characteristics of CA membranes, also at the highest GO loadings used, with a porosity of about 80%, but the presence of GO influenced the pore sizes, that ranged between about 9 and 16 µm. The starting GO and the nanocomposite structures were characterized by the combination of various techniques that evidences as Sulphur and Chlorinated impurities, that were present in the starting GO material, were completely eliminated by the interaction with SC-CO 2 during structures formation; moreover, a partial reduction of GO to graphene was also observed. . Compared to graphene, GO is heavily oxygenated and its basal plane carbon atoms are decorated with epoxide and hydroxyl groups and its edge atoms with carbonyl and carboxyl groups. Hence, GO is highly hydrophilic and the presence of these functional groups reduces interplanar forces, which can improve the interfacial interaction between GO and some polymers and, thus, the dispersion of GO in polymer matrices 2,3 . Many factors can affect the final properties and applications of GO/polymer nanocomposites 4 , among these: kind of GO used, its dispersion state in the polymeric matrix and interfacial interactions, the amount of wrinkling, its network structure in the matrix and its purity.Various attempts have been proposed in the literature to realize GO/polymers composite structures [5][6][7][8][9][10][11][12][13][14][15] . The processes proposed until now (i.e., phase inversion, casting, electrospinning) present several limitations; for example, residues of organic solvents of GO synthesis are typically found at the end of these processes, causing problems, in particular, for biomedical applications. Moreover, a homogeneous distribution of GO in the polymeric matrix is difficult to obtain, since the cohesive forces among GO layers tend to produce restacking. GO composites performance is strongly related to its level of exfoliation (i.e., separation of the layers). Exfoliated GO allows the largest interfacial contact with the polymer matrix, improving the properties of the composites. For this reason, several techniques have been implemented to increase the GO exfoliation degree. In particular, solvent-based exfoliation and thermal exfoliation techniques emerged as two preferred routes for this step [16][17][18][19] . [30][31][32][33] . Due to molecular size of CO 2 and its polarizability, it has the potential to pass through the solid porous layers 34 and, when supercritical conditions are reached, CO 2 diffusivity can favor layers expansion and exfoliation [31][32][33] . It is also possible to...

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Crumpled Nanopaper from Graphene Oxide

Cited by 165 publications

References 16 publications

Statistical Mechanics of Thin Spherical Shells

Statistical Mechanics of Thin Spherical Shells

Structure of graphene and its disorders: a review

Formation of Cellulose Acetate–Graphene Oxide Nanocomposites by Supercritical CO₂ Assisted Phase Inversion

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Crumpled Nanopaper from Graphene Oxide

Cited by 165 publications

References 16 publications

Statistical Mechanics of Thin Spherical Shells

Statistical Mechanics of Thin Spherical Shells

Structure of graphene and its disorders: a review

Formation of Cellulose Acetate–Graphene Oxide Nanocomposites by Supercritical CO2 Assisted Phase Inversion

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Product

Resources

About

Formation of Cellulose Acetate–Graphene Oxide Nanocomposites by Supercritical CO₂ Assisted Phase Inversion