Compression behavior of simply-supported and fully embedded monolayer graphene: Theory and experiment

Koukaras, Emmanuel Ν.; Androulidakis, Charalampos; Anagnostopoulos, George; Papagelis, Konstantinos; Galiotis, Costas

doi:10.1016/j.eml.2016.03.016

Cited by 18 publications

(31 citation statements)

References 40 publications

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“…The critical strain for the initiation of wrinkling strongly depends on the magnitude of adhesion with the underline substrate and was found to be ∼−0.30% for a single layer graphene on PMMA/SU-8. 13 Herein, the form of failure of simply supported single layer graphene under compression was examined by AFM and MD simulations as well. The AFM results for a single layer graphene on a PMMA/SU-8 substrate at rest (∼0.00%) and under ∼−1.00% compressive strain are represented in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…When a simply supported or embedded graphene flake is subjected to uniaxial tension, it is in fact loaded in compression in the lateral direction due to the Poisson's shrinkage of the polymer (which is relatively larger than that of graphene). Wrinkling of supported graphene under compression has been examined in various studies, 8,[13][14][15] as well as the effect of heavy wrinkled topography present in CVD graphene to the tensile performance and the reinforcing capabilities. [16][17][18] On the other hand, little attention has been given to the formation of these instabilities under tension.…”

Section: Introductionmentioning

confidence: 99%

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Wrinkling formation in simply-supported graphenes under tension and compression loadings

et al. 2017

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Wrinkles in supported graphenes can be formed either by uniaxial compression or uniaxial tension beyond a certain critical load depending on the mode of loading. In the first case, the wrinkling direction is normal to the compression axis whereas in tension, wrinkles of the same pattern are formed parallel to the loading direction due to Poisson's (lateral) contraction. Herein we show by direct AFM observations that in simply-supported graphenes such instabilities appear as periodic wrinkles over existing stochastic undulations caused by the underlying-substrate-roughness. The critical strain for the generation of these wrinkles in both tension and compression is less than 1% which particularly for the former is far lower than the predicted tensile strain to fracture of suspended graphene estimated at ∼30%. Based on these findings, a constitutive model that provides the critical tensile strain for induced buckling in the lateral direction is proposed that depends only on the graphene-support interaction and not on the nature of the substrate. Understanding the wrinkling failure of graphenes under strain is of paramount importance as it leads to new threshold limits beyond which the physical-mechanical properties of graphene are impaired.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wrinkling formation in simply-supported graphenes under tension and compression loadings

et al. 2017

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“…where K W is the Winkler's modulus, K l is the stiffness of the springs that bind the polymer to the outer layer, K gr is the stiffness of the springs that bond the individual graphene layers to each other with unit of Pa/m, and n is the number of layers of the few layer graphene. The stiffness of the springs that connect the outer graphene layer to the polymer is taken to be K 1 =3 GPa/nm based on experiments of simply supported mono-layer [19].…”

Section: Spring-in-seriesmentioning

confidence: 99%

Non-Eulerian behavior of graphitic materials under compression

Androulidakis

Koukaras

Hadjinicolaou

et al. 2018

Carbon

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The mechanical behavior of graphitic materials is greatly affected by the weak interlayer bonding with van der Waals forces for a range of thickness from nano to macroscale. Herein, we present a comprehensive study of the effect of layer thickness on the compression behavior of graphitic materials such as graphene which are fully embedded in polymer matrices. Raman Spectroscopy was employed to identify experimentally the critical strain to failure of the graphitic specimens. The most striking finding is that, contrary to what would be expected from Eulerian mechanics, the critical compressive strain to failure decreases with increase of flake thickness. This is due to the layered structure of the material and in particular the weak cohesive forces that hold the layers together. The plate phenomenology breaks down for the case of multi-layer graphene, which can be approached as discrete single layers weakly bonded to each other. This behavior is modelled here by considering the interlayer bonding (van der Waals forces) as springs in series, and very good agreement was found between theory and experiment. Finally, it will be shown that in the post failure regime multi-layer graphenes exhibit negative stiffness and thus behave as mechanical metamaterials.

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“…For comparison, in the case of perfectly flat bands and a constant ∆ FB we have the result [10] In the flat band regime the ratio tends approximately to a constant as in Eq. (33). and in TBG [14] within the same interaction model k B T c ≈ 0.25 max ∆(T = 0).…”

Section: B Critical Doping Level and Temperaturementioning

confidence: 99%

Flat-band superconductivity in periodically strained graphene: mean-field and Berezinskii–Kosterlitz–Thouless transition

Peltonen

Heikkilä²

2020

J. Phys.: Condens. Matter

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In the search of high-temperature superconductivity one option is to focus on increasing the density of electronic states. Here we study both the normal and s-wave superconducting state properties of periodically strained graphene, which exhibits approximate flat bands with a high density of states, with the flatness tunable by the strain profile. We generalize earlier results regarding a one-dimensional harmonic strain to arbitrary periodic strain fields, and further extend the results by calculating the superfluid weight and the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature TBKT to determine the true transition point. By numerically solving the self-consistency equation, we find a strongly inhomogeneous superconducting order parameter, similarly to twisted bilayer graphene. In the flat band regime the order parameter magnitude, critical chemical potential, critical temperature, superfluid weight, and BKT transition temperature are all approximately linear in the interaction strength, which suggests that high-temperature superconductivity might be feasible in this system. We especially show that by using realistic strain strengths TBKT can be made much larger than in twisted bilayer graphene, if using similar interaction strengths. We also calculate properties such as the local density of states that could serve as experimental fingerprints for the presented model. :1910.06671v2 [cond-mat.supr-con] arXiv

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Compression behavior of simply-supported and fully embedded monolayer graphene: Theory and experiment

Cited by 18 publications

References 40 publications

Wrinkling formation in simply-supported graphenes under tension and compression loadings

Wrinkling formation in simply-supported graphenes under tension and compression loadings

Non-Eulerian behavior of graphitic materials under compression

Flat-band superconductivity in periodically strained graphene: mean-field and Berezinskii–Kosterlitz–Thouless transition

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