Bending the World’s Hardest Material
We are delighted to share that Professor Subra Suresh, President, NTU Singapore, has published a research article, entitled ‘Ultralarge elastic deformation of nanoscale diamond’ in Science. The international assembly of scientists from USA, China, Korea and Hong Kong demonstrated that diamond can be flexible and stretched when fabricated into nanoscale needles. This revolution debunks norms and long-established “truths” of the macro- and microscopic regimes. At the nanoscale, new and unexpected properties are manifested which are easily predicted from the micro-scale behaviour.
Being the world’s hardest natural material, diamonds have significant rigidity and durability, which result in brittle fracture during deformation. In this work, nanoscale diamond needles were fabricated by plasma-induced etching of diamond thin films deposited on silicon substrates through chemical vapour deposition. Quantitative in-situ nanomechanical characterization was performed with a nanoindenter system linked to a scanning electron microscope. The study showed the occurrence of ultralarge, fully reversible elastic deformation in both single- and polycrystalline nanoscale (300 nm) diamond needles. By complementing the experimental observations with computational simulations, such as the finite element method (FEM) and molecular dynamics, and characterization of structural features pre- and post-deformation, the team attributed the phenomena of concurrent high strength and large elastic strain to the deficiency of defects in the nanoscale diamond needles. In addition, the relatively smooth surface, when compared to the macro- and microscale specimens, also contributed to the phenomena. This exciting discovery paves the way forward for optimized designs of new diamond nanostructures for a plethora of applications in bioimaging and biosensing, drug delivery, data storage, and strain-mediated nanomechanical resonators.
The article may be found via this link.