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

Abstract

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.

Monolayer Nanosheets with an Extremely High Drug Loading toward Controlled Delivery and Cancer Theranostics

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have shown excellent performances in cancer therapy. [18][19][20][21] Moreover, 2D nanomaterials normally suffer from a low drug loading content (LC) and encapsulation efficiency (EE), if the fine structure and drugcarrier interaction cannot be elaborately regulated. [11][12][13][14][15][16][17] However, the previously reported ultrathin 2D nanomaterials are mainly based on a "top-down" mechanical-exfoliation strategy, which show difficulties in the control over particle size, thickness, morphology, and uniformity.

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Measuring Interlayer Shear Stress in Bilayer Graphene

“…In fact, the interlayer vdW interactions for most 2D materials are relatively weak in the mechanical sense, so individual layers with atomically smooth surfaces are highly lubricated [16]. Recently, the interlayer shear behavior has been explored by recording the interaction between multilayer nanosheets and a scanning tip via frictional force microscopy [17,18] or an indentation tip via an atomic force microscope (AFM) [19,20]. Although these tip-based measurements have unveiled interesting dynamics due to adhesive and frictional interactions, the understanding of interlayer deformation and failure mechanisms within multilayered 2D structures remains limited, and quantitative characterization of the interlayer interactions has been experimentally challenging and yet to emerge.…”

Exfoliating a CdII–Purine Framework: Conversion of Nanosheets‐to‐Nanofibers and Studies of Elastic and Capacitive Properties

“…Metal–organic frameworks (MOFs) and inorganic hybrid materials have been explored for their mechanical characteristics at nanoscale for fabricating rigid or soft substances desirable for various applications . There are ample reports on the measurement of elastic properties of 2D materials by using direct and conventional techniques.…”

“…We have carried out many such studies revealing interesting characteristics of purines, peptides, and their conjugates/derivatives on different surfaces . With the various existent modes in AFM, it is possible to analyze properties of 2D and 1D nanostructures, such as determination of capacitive properties by scanning Kelvin probe force microscopy (SKPFM) and Young's modulus by amplitude modulation–frequency modulation (AM–FM) AFM . The technique provides an insight into the properties possessed by the material, which can then be followed by detailed analyses by using the known conventional and standard methods.…”