Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rice researchers unzip the future

17.04.2009
Simple process makes thin, conductive nanoribbons

Scientists at Rice University have found a simple way to create basic elements for aircraft, flat-screen TVs, electronics and other products that incorporate sheets of tough, electrically conductive material.

And the process begins with a zipper.

Research by the Rice University lab of Professor James Tour, featured on the cover of the April 16 issue of the journal Nature, has uncovered a room-temperature chemical process that splits, or unzips, carbon nanotubes to make flat nanoribbons. The technique makes it possible to produce the ultrathin ribbons in bulk quantities.

These ribbons are straight-edged sheets of graphene, the single-layer form of common graphite found in pencils. You'd have to place thousands of them side by side to equal the width of a human hair, but tests show graphene is 200 times stronger than steel.

"If you want to make conductive film, this is what you want," said Tour, Rice's Chao Professor of Chemistry and also a professor of mechanical engineering and materials science and computer science. "As soon as we started talking about this process, we began getting calls from manufacturers that recognized the potential."

The process involves sulfuric acid and potassium permanganate, which have been in common use since the 1890s. This chemical one-two punch attacks single and multiwalled carbon nanotubes, reacting with the carbon framework and unzipping them in a straight line.

The unzipping action can start on the end or in the middle, but the result is the same – the tubes turn into flat, straight-edged, water-soluble ribbons of graphene. When produced in bulk, these microscopic sheets can be "painted" onto a surface or combined with a polymer to let it conduct electricity.

Nanotubes have been used for that purpose already. "But when you stack two cylinders, the area that is touching is very small," Tour said. "If you stack these ribbons into sheets, you have very large areas of overlap. As an additive for materials, it's going to be very large, especially for conductive materials."

He credited Rice postdoctoral research associate Dmitry Kosynkin with the discovery. Kosynkin is lead author of the Nature paper, with contributions from graduate students Amanda Higginbotham, Jay Lomeda and B. Katherine Price, postdoctoral researcher Alexander Sinitskii, visiting scientist Ayrat Dimiev and Tour.

Kosynkin made the find while studying oxidation processes involving nanotubes. "Dmitry came to me and said he had nanoribbons," recalled Tour. "It took a while to convince me, but as soon as I saw them I realized this was huge."

Nearly all of the nanotubes subjected to unzipping turn into graphene ribbons, Tour said, and the basic process is the same for single or multiwalled tubes. Single-walled carbon nanotubes convert to sheets at room temperature and are good for small electronic devices because the width of the unzipped sheet is highly controllable. But the multiwalled nanotubes are much cheaper starting materials, and the resulting nanoribbons would be useful in a host of applications.

That's why Tour is banking on bulk, made possible by processing multiwalled tubes, which unzip in one hour at 130 to 158 degrees Fahrenheit. (Until now, making such material in more than microscopic quantities has involved a chemical vapor deposition process at more than 1,500 F.) "Multiwalled carbon nanotubes are concentric tubes, like Russian nesting dolls," he said. "We cut through 20 walls, one at a time, during the reaction process."

At first, the process of isolating nanoribbons "involved a lot of excruciating washing," he said. "But we've found a much easier way, which we needed to do to get industry to start taking it from here.

"If a company wants to produce these, they could probably start selling small quantities within six months. To scale it up and sell ton quantities, it might take a couple of years. That's just a matter of having the right reactors. But the chemistry is all there. It's very simple."

Tour is excited by the possibility that conductive nanoribbons could replace indium tin oxide (ITO), a material commonly used in flat-panel displays, touch panels, electronic ink and solar cells. "ITO is very expensive, so lots of people are looking for substitutes that will give them transparency with conductivity," he said.

"People have made thin films of nanotubes that fit the bill, but I think this will enable even thinner films, with the equivalent conductivity or better."

He envisioned nanoribbon-coated paper that could become a flexible electronic display, and he's already experimenting with nanoribbon-infused ink for ink-jet printers. "We're printing transistors and radio-frequency identification tags, printing electronics with these inks," he said.

"This is going to be the new material for many applications."

Tour said discussions are already underway with several companies looking into large-scale production of nanoribbons and with others interested in specific applications for nanoribbons in their core product technologies. Formal industrial partnering has already begun through Rice's Office of Technology Transfer.

The work was funded by the Defense Advanced Research Projects Agency, the Federal Aviation Administration and Wright Patterson Air Force Laboratory through the U.S. Air Force Office of Scientific Research.

The paper can be found at www.nature.com. 


A podcast with Tour will be posted online at www.nature.com/nature/podcast.

Mike Williams | EurekAlert!
Further information:
http://www.rice.edu

More articles from Process Engineering:

nachricht Innovative process for environmentally friendly manure treatment comes onto the market
03.05.2018 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

nachricht No compromises: Combining the benefits of 3D printing and casting
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>