Tag Archives: diamond

Making diamonds at room temperature with a new carbon material

Scientists at North Carolina State University (NCSU) claim to have found a new phase for solid carbon which allows them to create diamond materials at room temperature. From a Nov. 30, 2015 news item on Nanowerk,

Researchers from North Carolina State University have discovered a new phase of solid carbon, called Q-carbon, which is distinct from the known phases of graphite and diamond. They have also developed a technique for using Q-carbon to make diamond-related structures at room temperature and at ambient atmospheric pressure in air.

Phases are distinct forms of the same material. Graphite is one of the solid phases of carbon; diamond is another.

“We’ve now created a third solid phase of carbon,” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and lead author of three [?] papers describing the work. “The only place it may be found in the natural world would be possibly in the core of some planets.”

A Nov. 30, 2015 NCSU news release (also on EurekAlert), which originated the news item, describes some of the new material’s properties,

Q-carbon has some unusual characteristics. For one thing, it is ferromagnetic – which other solid forms of carbon are not. [definition from its Wikipedia entry: Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets.]

“We didn’t even think that was possible,” Narayan says.

In addition, Q-carbon is harder than diamond, and glows when exposed to even low levels of energy.

“Q-carbon’s strength and low work-function – its willingness to release electrons – make it very promising for developing new electronic display technologies,” Narayan says.

But Q-carbon can also be used to create a variety of single-crystal diamond objects. …

The news release describes the process for creating Q-carbon,

Researchers start with a substrate, such as such as sapphire, glass or a plastic polymer. The substrate is then coated with amorphous carbon – elemental carbon that, unlike graphite or diamond, does not have a regular, well-defined crystalline structure. The carbon is then hit with a single laser pulse lasting approximately 200 nanoseconds. During this pulse, the temperature of the carbon is raised to 4,000 Kelvin (or around 3,727 degrees Celsius) and then rapidly cooled. This operation takes place at one atmosphere – the same pressure as the surrounding air.

The end result is a film of Q-carbon, and researchers can control the process to make films between 20 nanometers and 500 nanometers thick.

By using different substrates and changing the duration of the laser pulse, the researchers can also control how quickly the carbon cools. By changing the rate of cooling, they are able to create diamond structures within the Q-carbon.

“We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films, with applications for drug delivery, industrial processes and for creating high-temperature switches and power electronics,” Narayan says. “These diamond objects have a single-crystalline structure, making them stronger than polycrystalline materials. And it is all done at room temperature and at ambient atmosphere – we’re basically using a laser like the ones used for laser eye surgery. So, not only does this allow us to develop new applications, but the process itself is relatively inexpensive.”

And, if researchers want to convert more of the Q-carbon to diamond, they can simply repeat the laser-pulse/cooling process.

If Q-carbon is harder than diamond, why would someone want to make diamond nanodots instead of Q-carbon ones? Because we still have a lot to learn about this new material.

“We can make Q-carbon films, and we’re learning its properties, but we are still in the early stages of understanding how to manipulate it,” Narayan says. “We know a lot about diamond, so we can make diamond nanodots. We don’t yet know how to make Q-carbon nanodots or microneedles. That’s something we’re working on.”

NC State has filed two provisional patents on the Q-carbon and diamond creation techniques.

While the news release mentions Narayan is the lead author of three papers about this work, only two papers are cited at the end of the news release.

Here are the links and citations,

Research Update: Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air by Jagdish Narayan and Anagh Bhaumik. APL Mater. 3, 100702 (2015); http://dx.doi.org/10.1063/1.4932622 [Published Oct. 7, 2015]

Novel Phase of Carbon, Ferromagnetism and Conversion into Diamond by Jagdish Narayan and Anagh Bhaumik. Published online Nov. 30 [, 2015] in the Journal of Applied Physics  DOI: 10.1063/1.4936595

Both articles are open access.

Virtual lego used to simulate self-assembling crystal structures

The Jan. 17, 2013 news release on EurekAlert describes a ‘soft’ or virtual lego computer simulation developed at the University of Vienna (Austria),

In developing these novel self-assembling materials, postdoc Barbara Capone has focused on the design of organic and inorganic building blocks, which are robust and can be produced at large scale. Capone has put forward, together with her colleagues at the Universities of Vienna and Mainz, a completely new pathway for the construction of building blocks at the nanoscale.

The team of researchers has shown that so-called block copolymer stars – that means polymers that consist of two different blocks and they are chemically anchored on a common point – have a robust and flexible architecture and they possess the ability to self-assemble at different levels. At the single-molecule level, they first order as soft patchy colloids which serve then as “soft Lego” for the emergence of larger structures. At the next level of self-assembly, the colloids form complex crystal structures, such as diamond or cubic phases.

The spatial ordering in the crystals can be steered through the architecture of the “soft Lego” and opens up the possibility for the construction of new materials at the macroscopic scale with desired structure. In this way, crystals can be built that have applications in, e.g., photonics, acting as filters for light of certain frequencies or as light guides.

You can find illustrations of the ‘diamond’ and the ‘cube’ produced by Capone and her colleagues with the news release on EurekAlert or here at the University of Vienna’s media portal where you may be able to find more information if you can read German. Alternatively, you can read the research paper,

Telechelic Star Polymers as Self-Assembling Units from the Molecular to the Macroscopic Scale by Barbara Capone, Ivan Coluzza, Federica LoVerso, Christos N. Likos, and Ronald Blaak in Physical Review Letters 109 [issue no. 23], 238301 (2012) [5 pages]DOI:10.1103/PhysRevLett.109.238301

This article is behind a paywall.