We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.

/pdf/measurement-of-the-elastic-properties-and-intrinsic-strength-27nythtm75.pdf

Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

/pdf/science-and-technology-roadmap-for-graphene-related-two-4q9m7czlkc.pdf

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within our environment safely and effectively. Interest in large-area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large-area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e-skin) akin to human skin. E-skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self-powering). Continued rapid progress in this area is promising for the development of a fully integrated e-skin in the near future.

25th Anniversary Article: The Evolution of Electronic Skin (E-Skin): A Brief History, Design Considerations, and Recent Progress

Synthesis of carbon nanotubes by chemical vapor deposition over patterned catalyst arrays leads to nanotubes grown from specific sites on surfaces. The growth directions of the nanotubes can be controlled by van der Waals self-assembly forces and applied electric fields. The patterned growth approach is feasible with discrete catalytic nanoparticles and scalable on large wafers for massive arrays of novel nanowires. Controlled synthesis of nanotubes opens up exciting opportunities in nanoscience and nanotechnology, including electrical, mechanical, and electromechanical properties and devices, chemical functionalization, surface chemistry and photochemistry, molecular sensors, and interfacing with soft biological systems.

/pdf/carbon-nanotubes-synthesis-integration-and-properties-1kq36jxaj3.pdf

Carbon Nanotubes: Synthesis, Integration, and Properties

Carbon nanotubes: opportunities and challenges

The effects of mechanical deformation on the electrical properties of carbonnanotubes are of interest given the practical potential of nanotubes in electromechanicaldevices, and they have been studied using both theoretical1,2,3,4and experimental5,6 approaches. One recent experiment6 used the tip of an atomic force microscope (AFM) to manipulate multi-wallednanotubes, revealing that changes in the sample resistance were small unlessthe nanotubes fractured or the metal–tube contacts were perturbed. Butit remains unclear how mechanical deformation affects the intrinsic electricalproperties of nanotubes. Here we report an experimental and theoretical elucidationof the electromechanical characteristics of individual single-walled carbonnanotubes (SWNTs) under local-probe manipulation. We use AFM tips to deflectsuspended SWNTs reversibly, without changing the contact resistance; insitu electrical measurements reveal that the conductance of an SWNT samplecan be reduced by two orders of magnitude when deformed by an AFM tip. Ourtight-binding simulations indicate that this effect is owing to the formationof local sp3 bonds caused by the mechanical pushingaction of the tip.

Reversible electromechanical characteristics of carbon nanotubes under local-probe manipulation

A simulation of the deflection of a single wall nanotube under the manipulation of an atomic force microscope tip revealed the key feature characterizing the deformation at relatively small bending angles to be a reversible transition from $s{p}^{2}$ to $s{p}^{3}$ bonding configurations in the bending region, leading to a 2 orders of magnitude reduction in conductance consistent with our most recent experimental observation. A local analysis elucidating the underlying physics of the findings is also discussed.

Controllable reversibility of an sp(2) to sp(3) transition of a single wall nanotube under the manipulation of an AFM tip: A nanoscale electromechanical switch?

Leo Alexseyev

Papers

Reversible electromechanical characteristics of carbon nanotubes under local-probe manipulation

Controllable reversibility of an sp(2) to sp(3) transition of a single wall nanotube under the manipulation of an AFM tip: A nanoscale electromechanical switch?