Diamonds are one of the hardest substances that we know of, so trying to bend a bit of one might sound like attempting the impossible. Yet that is exactly what a team over at MIT have just managed to do.

The impressive new work has found that when diamonds are grown into nanoneedles, the structures can be bent and stretched before snapping back into shape, not unlike rubber. Publishing their results in the journal Science, the researchers hope that the findings could allow for diamonds to be used in a whole host of new technologies, from drug delivery and data storage to sensing and optoelectronics.

We think of diamonds as a solid structure that forms the hardest known natural material, but researchers can grow the mineral into other shapes. The researchers of this latest study got the diamond to form tiny needles similar in shape to the rubber tips on the backs of some toothbrushes, just a hell of a lot smaller.

They then tested the strength of these minuscule projections by pushing down on them with an equally small tool. Amazingly, they found that the diamond spikes were not as solid or brittle as you might expect, but could instead be flexed and stretched by as much as 9 percent without snapping, before then returning to their original shape.

Diamonds in their traditional bulk form can only flex below 1 percent, meaning that the team managed to alter radically the properties of the hard material. “It was very surprising to see the amount of elastic deformation the nanoscale diamond could sustain,” explains co-author Daniel Bernoulli.

This newfound bendiness could have all sorts of implications. The deformation of the crystal can alter the mechanical properties, as well as the thermal, optical, electrical, and chemical reactions of the substance, potentially expanding what the nanostructured diamonds can be used for.

“The surprise finding of ultralarge elastic deformation in a hard and brittle material – diamond – opens up unprecedented possibilities for tuning its optical, optomechanical, magnetic, phononic, and catalytic properties through elastic strain engineering,” says Yonggang Huang, a professor of civil and environmental engineering and mechanical engineering at Northwestern University, but who was not actually involved in the study. 

Hopefully, this work can go on to be used in a whole range of new technology at some point in the future.