Scientists Have Figured Out How To Make Diamonds Bend And Stretch Like Rubber

This unexpected discovery opens the door to a variety of applications for diamond-based devices, according to MIT.

Diamond in tweezers.
AlmarinaStudio / Shutterstock

This unexpected discovery opens the door to a variety of applications for diamond-based devices, according to MIT.

Diamonds may be the hardest natural material found on planet Earth, but an international team of researchers has found a way to manipulate the tough structure of diamonds and bend them to their will — literally.

A study published last week in the journal Science reveals that, although famously brittle, diamonds can deform elastically, in the same way that rubber does, if you look at them from a nanoscale viewpoint.

The research, conducted by scientists from the Massachusetts Institute of Technology (MIT), Hong Kong, Singapore, and Korea, revealed that diamonds can become flexible “when grown in extremely tiny, needle-like shapes,” states an MIT news release.

In order to observe how much the properties of diamond can differ in nanoscale, the researchers took thin films of artificial diamonds and etched tiny needles out of them, Newsweek reports.

According to senior co-author Ming Dao, from the Department of Materials Science and Engineering at MIT, the ultrafine diamond needles, only 300 nanometers wide (a nanometer is one billionth of a meter), can bend and stretch by as much as nine percent before snapping back to their original shape.

That’s more than eight times higher compared with the maximum tensile strength of ordinary diamond in bulk form, which MIT postdoctoral researcher Daniel Bernoulli notes is of well below one percent.

“It was very surprising to see the amount of elastic deformation the nanoscale diamond could sustain,” Bernoulli says in the news release.

The researchers explain that the key to these results laid in the small size of the diamond needles, “which allowed for very smooth-surfaced, defect-free diamonds,” the team wrote in their paper.

“We developed a unique nanomechanical approach to precisely control and quantify the ultralarge elastic strain distributed in the nanodiamond samples,” says study senior co-author Yang Lu, from the Shenzhen Research Institute at the City University of Hong Kong, China.

Using a technique called “elastic strain engineering,” which altered the mechanical properties of diamond crystals by applying ultralarge elastic strain, the team observed that the elastic deformation they obtained was close to the known ideal tensile strength of diamond — the theoretical limit achievable by defect-free diamond, notes RtoZ.org.

Senior co-author Subra Suresh, from Nanyang Technological University in Singapore, told I4U News that the results were so unexpected that the team ran the experiments again under different conditions to make sure they were accurate.

This spectacular find has a very wide array of possible applications, particularly in microelectronics and drug delivery, the team points out in the study.

For instance, diamonds could be used as biocompatible carriers to deliver drugs directly into cancer cells. Other options include sensing, data storage, actuation, biocompatible in vivo imaging, and optoelectronics, MIT details in the news release.