During brittle fracture, the energy needed to overcome the chemical bonding within a material is supplied by the surface energy (γ) released upon cracking. The former scales quadratically with strain while latter is linear such that there is a characteristic length, L, below which a pre-existing micro-crack is infinitely stable (Nat. Comm. 5, 3782). Large-area graphene or other 2D materials prepared by CVD, albeit mechanically robust, usually carry intrinsic nanometer-sized defects. Recent work by Mitchell et al. (Nat. Mat. 16, 89) showed that the imposition of a rigid substrate with Gaussian curvature could predictably control the macroscopic crack growth upon stretching. In this work, we ask if a similar imposition of a strain field at a scale 1000 times smaller could likewise guide spontaneous crack formation in molecularly thin 2D materials, as a scalable nanofabrication method to produce new types of electronic colloids capable of device operations.

2D materials grafted colloidal microparticles

255th National Meeting (2018)

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