Elastic and Shear Moduli of Single-Walled Carbon Nanotube Ropes

Salvetat, Jean‐Paul; Briggs, G. Andrew D.; Bonard, Jean–Marc; Bacsa, Revathi; Kulik, Andrzej; Stöckli, Thomas; Burnham, Nancy A.; Forró, Lászlø

doi:10.1103/physrevlett.82.944

Cited by 1,403 publications

(888 citation statements)

References 15 publications

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“…A similar reduction of E has been observed upon bundling of single-walled carbon nanotubes. 28 This behavior is characteristic of stiffened structures and can be understood on the basis of competing bending and shear forces. For stiffer structures like the thicker and shorter multilayers, bending deflections are almost negligible and shear strains play a dominant role.…”

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confidence: 99%

Elastic Properties of Chemically Derived Single Graphene Sheets

2008

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The elastic modulus of freely suspended graphene monolayers, obtained via chemical reduction of graphene oxide, was determined through tip-induced deformation experiments. Despite their defect content, the single sheets exhibit an extraordinary stiffness (E ) 0.25 TPa) approaching that of pristine graphene, as well as a high flexibility which enables them to bend easily in their elastic regime. Built-in tensions are found to be significantly lower compared to mechanically exfoliated graphene. The high resilience of the sheets is demonstrated by their unaltered electrical conductivity after multiple deformations. The electrical conductivity of the sheets scales inversely with the elastic modulus, pointing toward a 2-fold role of the oxygen bridges, that is, to impart a bond reinforcement while at the same time impeding the charge transport.Recent experiments have revealed the thermodynamic stability of graphene under ambient conditions, 1-3 which strongly revived the interest in the electrical and mechanical properties of this fascinating carbon nanostructure. Two major methods have been established for the fabrication of graphene monolayers, namely, mechanical exfoliation of graphite 2 and vacuum graphitization of silicon carbide. 3,4 More recently, chemical reduction of graphene oxide (GO) has been reported as an alternative, solution-based route, for obtaining graphenelike sheets which offers the advantages of being cheap and up-scalable. [5][6][7][8] Even though GO is a good insulator, deoxygenation has been shown to substantially enhance its electrical conductivity, albeit the obtained values of ∼1 S/cm remain 2-3 orders of magnitude below that of pristine graphene. 6,7 Due to the limited efficiency of the reduction process, the obtained sheets still contain residual oxygenated functional groups of the starting material. Microscopic studies of the reduced GO also indicate the coexistence of graphitic regions with defect clusters 6,9 in agreement with proposed models. [9][10][11] In addition to its interesting electrical characteristics, this 2D material is expected to have also unique mechanical properties. Recent studies have witnessed its suitability for the fabrication of composites 12,13 and paperlike materials 14 with excellent mechanical properties. However, in order to promote its application in nanotechnology, the mechanical characterization of single sheets is of upmost relevance.Here we present a study of the mechanical and electrical properties of suspended, chemically reduced GO single sheets. Graphite oxide prepared via Hummers method 15 was dispersed in water, deposited onto a Si/SiO 2 substrate, and subsequently reduced by hydrogen plasma treatment. The obtained samples exhibited a high yield of monolayers with lateral dimensions of 0.1-5 µm. Preselected layers were then contacted by standard e-beam lithography with Ti/Au electrodes. In order to freely suspend the layers (Figure 1), the samples were wet etched by buffered hydrofluoric acid, followed by critical point drying to prevent ...

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confidence: 99%

Elastic Properties of Chemically Derived Single Graphene Sheets

2008

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“…In the same way as Salvetat et al 20 did with carbon nanotubes, a single vimentin IF was modelled as a clamped beam that rests over a gap, i.e. a hole with a diameter L ∼250 nm in a porous substrate, and is being bent by pushing with an AFM tip.…”

Section: Theorymentioning

confidence: 99%

“…no shearing between their building blocks), the bending stiffness corresponds to the Young's modulus (E Young ). 19 In order to rigorously measure the E Bending value of a single vimentin IF, we applied a method developed by Salvetat et al 20 for the study of filamentous nanostructures. This method was successfully applied to another cytoskeletal filament moiety, to microtubules (MTs), 21 as well as to biopolymers such as amyloid fibrils (Sheena Radford, University of Leeds UK and Cait MacPhee, University of Cambridge UK, personal communications).…”

Section: Introductionmentioning

confidence: 99%

Exploring the Mechanical Properties of Single Vimentin Intermediate Filaments by Atomic Force Microscopy

Guzmán

Jeney

Kreplak

et al. 2006

Journal of Molecular Biology

106

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Intermediate filaments (IFs), together with actin filaments and microtubules, compose the cytoskeleton. Among other functions, IFs impart mechanical stability to cells when exposed to mechanical stress and act as a support when the other cytoskeletal filaments cannot keep the structural integrity of the cells. Here we present a study on the bending properties of single vimentin IFs in which we used an atomic force microscopy (AFM) tip to elastically deform single filaments hanging over a porous membrane. We obtained a value for the bending modulus of non-stabilized IFs between 300 MPa and 400 MPa. Our results together with previous ones suggest that IFs present axial sliding between their constitutive building blocks and therefore have a bending modulus that depends on the filament length. Measurements of glutaraldehyde-stabilized filaments were also performed to reduce the axial sliding between subunits and therefore provide a lower limit estimate of the Young's modulus of the filaments. The results show an increment of two to three times in the bending modulus for the stabilized IFs with respect to the non-stabilized ones, suggesting that the Young's modulus of vimentin IFs should be around 900 MPa or higher.

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Section: Introductionunclassified

“…Um aspecto importante é que dificilmente os NC são encontrados individualmente [8] . Os aglomerados de NC possuem propriedades mecânicas que variam com o tamanho dos mesmos, sendo que, quanto maior o tamanho do aglomerado, mais reduzida fica essa propriedade [9] .Além da sua utilização em nanocompósitos estruturais, os nanotubos também foram cotados para melhorar propriedades tribológicas dos nanocompósitos. Mesmo com o foco das pesquisas no campo da tribologia, durante muito tempo, ser nos nanocompósitos metálicos e cerâmicos, os de matriz polimérica têm ganhado espaço e sido cada vez mais estudados [10] .…”

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Propriedades mecânicas, tribológicas e térmicas de nanocompósitos de PLLA com nanotubos de carbono de paredes múltiplas

et al. 2014

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Resumo: Neste trabalho são estudados os efeitos da adição de nanotubos de carbono de parede múltipla (NCPM) em uma matriz de Poli(L-ácido láctico) (PLLA). Foras avaliadas duas rotas distintas de dispersão dos NCPM, uma utilizando agitação mecânica em solvente e a outra utilizando sonificação de alta energia em solvente. As propriedades mecânicas destes nanocompósitos foram avaliadas utilizando nanoindentação e microdureza vickers. Através da calorimetria exploratória diferencial foram determinadas as propriedades térmicas dos nanocompósitos (Tg, Tc, Tm e cristalinidade) obtidas. Por último, as propriedades tribológicas foram determinadas através de ensaios de deslizamento do tipo pino sobre disco, onde foram utilizadas diferentes cargas normais. As propriedades mecânicas e térmicas não foram significativamente afetadas pela adição do nanotubos, o que não se repetiu nas propriedades tribológicas, onde tanto o método de dispersão quanto a concentração de NCPM afetaram as propriedades. A micrografia das trilhas de desgaste sugere ainda que o mecanismo atuante foi modificado com a incorporação dos nanotubos, o mesmo pode ter acontecido nas amostras sonificadas. Palavras-chave: Nanotubos de carbono de paredes múltiplas, PLLA, propriedades mecânicas, propriedades tribológicas. Mechanical, Tribological and Thermal Properties of PLLA/MWCNT NanocompositesAbstract: This work studied the effects of the addition of Multiwalled Carbon Nanotubes (MWCNT) to a PLLA matrix. Two distinct methods of preparation were employed: a combination of a solvent/ mechanical stirring and a combination of a solvent/high energy sonication. The mechanical properties of the nanocomposites were determined by nanoindentation and by the Vickers hardness test. Thermal properties of the nanocomposites (T g , T c , T m and crystallinity degree) were determined by DSC. The tribological properties of the nanocomposites were determined by using a pin-on-disc apparatus. Mechanical and thermal properties did not present significant alterations, although tribological properties presented significant changes caused by the method of preparation and different loads. SEM images indicated that the wear mechanism was changed by the addition of MWCNT. Keywords: Multiwalled carbon nanotubes, PLLA, mechanical properties, tribological properties. IntroduçãoA partir do trabalho de Iijima [1] os nanotubos de carbono (NC) têm atraído a atenção da comunidade acadêmica devido as suas propriedades peculiares [2] . Após o primeiro nanocompósito de NC e epóxi [3] , os nanotubos já foram incorporado em mais de 30 matrizes diferentes [4] e o artigo de Iijima foi citado mais de 25 mil vezes [5] . Os NC podem ter uma única parede (NCPS) ou ter paredes múltiplas (NCPM) e essa diferença interfere diretamente nas suas propriedades e nas propriedades obtidas dos nanocompósitos [2] .Além do tipo de NC, outros fatores têm influência nas propriedades finais do nanocompósito. Entre esses fatores pode-se citar o diâmetro, o comprimento e a pureza dos nanotubos de carbono [6] . Além disso...

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Elastic and Shear Moduli of Single-Walled Carbon Nanotube Ropes

Cited by 1,403 publications

References 15 publications

Elastic Properties of Chemically Derived Single Graphene Sheets

Elastic Properties of Chemically Derived Single Graphene Sheets

Exploring the Mechanical Properties of Single Vimentin Intermediate Filaments by Atomic Force Microscopy

Propriedades mecânicas, tribológicas e térmicas de nanocompósitos de PLLA com nanotubos de carbono de paredes múltiplas

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