Mechanical deformations, such as buckling, crumpling, wrinkling, and delamination, are usually considered threats to mechanical integrity, which are to be avoided or reduced in the design of materials and structures.

However, if materials systems and applied stresses are carefully controlled, such mechanical instabilities can be tailored to create functional morphologies that can enable powerful new functions, which in turn advance applications in areas of electronics, energy, and even biological mechanisms.

A paper recently published by K.-S. Kim in MRS Advances, A New Subcritical Nanostructure of Graphene—Crinkle-Ruga Structure and Its Novel Properties, reports critical advances in mechanically deformable materials and their emerging functional properties. Kim’s research group at Brown University reports a fundamentally new deformation mode of atomically-thin materials, which they call ‘crinkles’.

Crinkles are a low-energy, subcritical mode shape that have sawtooth-shaped profiles with perfectly flat faces and highly curved tips of peaks and valleys. Kim demonstrates that a strong influence of charge localization leads to nano-level highly-curved structures at the tip of multilayer graphene crinkles. Furthermore, such strong charge localization leads to the attraction of C60 and lambda DNA on tips of their crinkle structures. This work not only showcases a fundamentally new deformation mode of atomically-thin materials but also demonstrates a new structural property (i.e., flexoelectricity), which could lead to significant advances in real world applications, such as DNA sequencing, self-powered sensors, and energy harvesters.

Complimentary access to this paper is available in MRS Advances, published jointly by the Materials Research Society and Cambridge University Press, until 31 August, 2018.

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