Pressurized blister tests show that the adhesion energies of graphene samples on silicon oxide are much higher than those measured in typical micromechanical structures.

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Ultrastrong adhesion of graphene membranes

It is shown that by controlling the relaxation of graphene adhered on a biaxially pre-stretched polymer substrate, graphene films can be reversibly crumpled and unfolded to form tailored hierarchical structures with tunable wettability and transmittance, and that the crumpled graphene–polymer laminates can be used as actuators.

/pdf/multifunctionality-and-control-of-the-crumpling-and-4mv177ltj7.pdf

Multifunctionality and control of the crumpling and unfolding of large-area graphene

National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (DMR-1121107)

This review examines the properties of graphene from an experimental perspective. The intent is to review the most important experimental results at a level of detail appropriate for new graduate students who are interested in a general overview of the fascinating properties of graphene. While some introductory theoretical concepts are provided, including a discussion of the electronic band structure and phonon dispersion, the main emphasis is on describing relevant experiments and important results as well as some of the novel applications of graphene. In particular, this review covers graphene synthesis and characterization, field-effect behavior, electronic transport properties, magnetotransport, integer and fractional quantum Hall effects, mechanical properties, transistors, optoelectronics, graphene-based sensors, and biosensors. This approach attempts to highlight both the means by which the current understanding of graphene has come about and some tools for future contributions.

/pdf/experimental-review-of-graphene-3aclfesva6.pdf

Experimental Review of Graphene

Atomically thin boron nitride (BN) nanosheets are important two-dimensional nanomaterials with many unique properties distinct from those of graphene, but investigation into their mechanical properties remains incomplete. Here we report that high-quality single-crystalline mono- and few-layer BN nanosheets are one of the strongest electrically insulating materials. More intriguingly, few-layer BN shows mechanical behaviours quite different from those of few-layer graphene under indentation. In striking contrast to graphene, whose strength decreases by more than 30% when the number of layers increases from 1 to 8, the mechanical strength of BN nanosheets is not sensitive to increasing thickness. We attribute this difference to the distinct interlayer interactions and hence sliding tendencies in these two materials under indentation. The significantly better interlayer integrity of BN nanosheets makes them a more attractive candidate than graphene for several applications, for example, as mechanical reinforcements.

/pdf/mechanical-properties-of-atomically-thin-boron-nitride-and-15z0fmm2c6.pdf

Mechanical properties of atomically thin boron nitride and the role of interlayer interactions

We examine the mechanical properties of graphene samples of thicknesses ranging from 1 to 17 atomic layers, placed on a microscale-corrugated elastic substrate. Using atomic force microscopy, we show that the graphene adheres to the substrate surface and can substantially deform the substrate, with larger graphene thicknesses creating greater deformations. We use linear elasticity theory to model the deformations of the composite graphene-substrate system. We compare experiment and theory, and thereby extract information about graphene’s bending rigidity, adhesion, critical stress for interlayer sliding, and sample-dependent tension.

/pdf/probing-the-mechanical-properties-of-graphene-using-a-pcoo0tin8e.pdf

Probing the mechanical properties of graphene using a corrugated elastic substrate

The exceptional mechanical properties of graphene have made it attractive for nano-mechanical devices and functional composite materials. Two key aspects of graphene's mechanical behavior are its elastic and adhesive properties. These are generally determined in separate experiments, and it is moreover typically difficult to extract parameters for adhesion. In addition, the mechanical interplay between graphene and other elastic materials has not been well studied. Here, we demonstrate a technique for studying both the elastic and adhesive properties of few-layer graphene (FLG) by placing it on deformable, micro-corrugated substrates. By measuring deformations of the composite graphene-substrate structures, and developing a related linear elasticity theory, we are able to extract information about graphene's bending rigidity, adhesion, critical stress for interlayer sliding, and sample-dependent tension. The results are relevant to graphene-based mechanical and electronic devices, and to the use of graphene in composite, flexible, and strain-engineered materials.

D. Z. Rocklin

Papers

Probing the mechanical properties of graphene using a corrugated elastic substrate

Probing the mechanical properties of graphene using a corrugated elastic substrate