New Nanomaterial, 'NanoBuds,' Combines Fullerenes and Nanotubes

Researchers have created a hybrid carbon nanomaterial that merges single-walled carbon nanotubes and spherical carbon-atom cages called fullerenes. The new structures, dubbed NanoBuds because they resemble buds sprouting on branches, may possess properties that are superior to fullerenes and nanotubes alone. They are described in the March 2007 edition of Nature Nanotechnology.

“Both fullerenes and single-walled carbon nanotubes exhibit many advantageous properties, but despite their similarities there have been very few attempts to physically merge them. The novel hybrid material we discovered merges the two into a single structure, in which the fullerenes are covalently bonded to the nanotubes,” said Esko Kauppinen, a scientist involved in the work, to PhysOrg.com. Kauppinen is a professor and researcher at the Helsinki University of Technology and the technology development organization VTT Biotechnology, both in Finland.

Synthesis of the NanoBuds began with the synthesis of single-walled carbon nanotubes (SWNTs) in a standard reactor. The resulting SWNTs seemed to be coated with clusters of carbon atoms, but a closer investigation, using an electron microscope, revealed that most of the clusters were actually fullerenes.

The fullerenes coating the nanotubes displayed unusual behavior. Using a transmission electron microscope, the researchers saw that these fullerenes did not move around upon the nanotube surface. This in not typical of fullerenes on SWNTs and indicated a strong fullerene/nanotube bond, which was further verified by several tests.

The group further probed the NanoBuds' structure using ultraviolet spectroscopy. The resulting UV spectra showed the attached fullerenes to be similar to C₇₀, the 70-carbon-atom fullerene, which has a slightly ellipsoidal shape compared to C₆₀ and other spherical fullerenes. This deviation from the characteristic fullerene sphere, or “bucky ball,” could have been due to the presence of covalently attached oxygen or hydrogen. Further measurements detected oxygen in each NanoBud, and a round of infrared spectroscopy revealed the presence of two types organic compounds known as ethers and esters. These compounds may act as bridge-like structures connecting the fullerenes to the nanotubes.

Kauppinen and his colleagues say that NanoBuds may find use as cold electron field emitters – materials that emit electrons at room temperature under a high applied electric field – due to the fullerenes' many curved surfaces, which make for better emitters that flat surfaces. Cold electron field emission is key to many technologies, including flat-panel displays and electron microscopes.

“We believe that NanoBuds may have other applications, such as molecular anchors to prevent SWNTs from slipping within composite materials,” says Kauppinen. “Additionally, since the optical and electrical properties of the fullerenes and nanotubes can be individually tuned, NanoBuds provide SWNTs with distinct regions of different electrical properties. This could be useful for many applications, including memory devices and quantum dots.”

Citation: Albert G. Nasibulin, Peter V. Pikhitsa, Hua Jiang, David P. Brown, Arkady V. Krasheninnikov, Anton S. Anisimov, Paula Queipo, Anna Moisala, David Gonzalez, Günther Lientschnig, Abdou Hassanien, Sergey D. Shandakov, Giulio Lolli, Daniel E. Resasco, Mansoo Choi, David Tománek and Esko I. Kauppinen, “A novel hybrid carbon material.” Nature Nanotechnology 2, 156-161 (2007)

Copyright 2007 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Related stories:

'Buckyballs' have high potential to accumulate in living tissue
Research at Purdue University suggests synthetic carbon molecules called fullerenes, or buckyballs, have a high potential of being accumulated in animal tissue, but the molecules also appear to break down in sunlight, perhaps reducing their possible environmental dangers.
How buckyballs hurt cells
A new study into the potential health hazards of the revolutionary nano-sized particles known as ‘buckyballs’ predicts that the molecules are easily absorbed into animal cells, providing a possible explanation for how the molecules could be toxic to humans and other organisms.
New nanotech products hitting the market at the rate of 3-4 per week
New nanotechnology consumer products are coming on the market at the rate of 3-4 per week, a finding based on the latest update to the nanotechnology consumer product inventory maintained by the Project on Emerging Nanotechnologies (PEN).
Researchers Make Breakthrough in Nanotechnology by Uncovering Conductive Property of Carbon-based Molecules
University of Pittsburgh researchers have discovered that certain organic—or carbon-based—molecules exhibit the properties of atoms under certain circumstances and, in turn, conduct electricity as well as metal. Detailed in the April 18 edition of Science, the finding is a breakthrough in developing nanotechnology that provides a new strategy for designing electronic materials, including inexpensive and multifunctional organic conductors that have long been considered the key to smaller, cheaper, and faster technologies.
Manufactured Buckyballs don't harm microbes that clean the environment
Even large amounts of manufactured nanoparticles, also known as Buckyballs, don't faze microscopic organisms that are charged with cleaning up the environment, according to Purdue University researchers.
Tiny buckyballs squeeze hydrogen like giant Jupiter
Hydrogen could be a clean, abundant energy source, but it's difficult to store in bulk. In new research, materials scientists at Rice University have made the surprising discovery that tiny carbon capsules called buckyballs are so strong they can hold volumes of hydrogen nearly as dense as those at the center of Jupiter.
Buckyball birth observed by Sandia nanotech researcher
Almost everyone in the scientific community has heard of buckyballs, but no one until Sandia’s Jianyu Huang has seen one being born.
Radio waves fire up nanotubes embedded in tumors, destroying liver cancer
Cancer cells treated with carbon nanotubes can be destroyed by non-invasive radio waves that heat up the nanotubes while sparing untreated tissue, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center and Rice University has shown in preclinical experiments.

News discussion:

Nano-Mechano in Nanotechnology news