Nanotechnology Now - Press Release: Researchers grind nanotubes to get nanoribbons: Rice-led experiments demonstrate solid-state carbon nanotube 'templates'

Home > Press > Researchers grind nanotubes to get nanoribbons: Rice-led experiments demonstrate solid-state carbon nanotube 'templates'

Researchers led by materials scientists at Rice University discovered that altering carbon nanotubes with carboxyl (COOH) and hydroxyl (OH) groups and grinding them together produces nanoribbons. The find could lead to novel nanostructured products with specific properties.

Credit: Mohamad Kabbani/Rice University

Abstract:
A simple way to turn carbon nanotubes into valuable graphene nanoribbons may be to grind them, according to research led by Rice University.

Researchers grind nanotubes to get nanoribbons: Rice-led experiments demonstrate solid-state carbon nanotube 'templates'

Houston, TX | Posted on June 15th, 2015

The trick, said Rice materials scientist Pulickel Ajayan, is to mix two types of chemically modified nanotubes. When they come into contact during grinding, they react and unzip, a process that until now has depended largely on reactions in harsh chemical solutions.

The research by Ajayan and his international collaborators appears in Nature Communications.

To be clear, Ajayan said, the new process is still a chemical reaction that depends on molecules purposely attached to the nanotubes, a process called functionalization. The most interesting part to the researchers is that a process as simple as grinding could deliver strong chemical coupling between solid nanostructures and produce novel forms of nanostructured products with specific properties.

"Chemical reactions can easily be done in solutions, but this work is entirely solid state," he said. "Our question is this: If we can use nanotubes as templates, functionalize them and get reactions under the right conditions, what kinds of things can we make with a large number of possible nanostructures and chemical functional groups?"

The process should enable many new chemical reactions and products, said Mohamad Kabbani, a graduate student at Rice and lead author of the paper. "Using different functionalities in different nanoscale systems could revolutionize nanomaterials development," he said.

Highly conductive graphene nanoribbons, thousands of times smaller than a human hair, are finding their way into the marketplace in composite materials. The nanoribbons boost the materials' electronic properties and/or strength.

"Controlling such structures by mechano-chemical transformation will be the key to find new applications," said co-author Thalappil Pradeep, a professor of chemistry at the Indian Institute of Technology Chennai. "Soft chemistry of this kind can happen in many conditions, contributing to better understanding of materials processing."

In their tests, the researchers prepared two batches of multi-walled carbon nanotubes, one with carboxyl groups and the other with hydroxyl groups attached. When ground together for up to 20 minutes with a mortar and pestle, the chemical additives reacted with each other, triggering the nanotubes to unzip into nanoribbons, with water as a byproduct.

"That serendipitous observation will lead to further systematic studies of nanotubes reactions in solid state, including ab-initio theoretical models and simulations," Ajayan said. "This is exciting."

The experiments were duplicated by participating labs at Rice, at the Indian Institute of Technology and at the Lebanese American University in Beirut. They were performed in standard lab conditions as well as in a vacuum, outside in the open air and at variable humidity, temperatures, times and seasons.

The researchers who carried out the collaboration on three continents still don't know precisely what's happening at the nanoscale. "It is an exothermic reaction, so the energy's enough to break up the nanotubes into ribbons, but the details of the dynamics are difficult to monitor," Kabbani said. "There's no way we can grind two nanotubes in a microscope and watch it happen. Not yet, anyway."

But the results speak for themselves.

"I don't know why people haven't explored this idea, that you can control reactions by supporting the reactants on nanostructures," Ajayan said. "What we've done is very crude, but it's a beginning and a lot of work can follow along these lines."

Co-authors are Rice graduate students Chandra Sekhar Tiwary, Sehmus Ozden and Yongji Gong; Pedro Autreto, Gustavo Brunetto and Professor Douglas Galvao of the State University of Campinas, Brazil; Anirban Som and K.R. Krishnadas of the Indian Institute of Technology Madras; Robert Vajtai, a senior faculty fellow at Rice, and Ahmad Kabbani, an adjunct faculty member at Rice and a professor of chemistry at the Lebanese American University, Beirut. Ajayan is chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

The research was supported by the Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative; the Brazilian National Council for Scientific and Technological Development, CAPES (Coordination of Improvement of Higher Education Personnel) and the São Paulo Research Foundation; the Center for Computational Engineering and Sciences at the State University of Campinas, and the Nano Mission, Government of India.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked among some of the top schools for best quality of life by the Princeton Review and for best value among private universities by Kiplinger's Personal Finance.

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth
713-348-6327

Mike Williams
713-348-6728

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark: