Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Rice science news - Nanotube, heal thyself

Abstract:
Pound for pound, carbon nanotubes are stronger and lighter than steel, but
unlike other materials, the miniscule carbon cylinders remain remarkably
robust even when chunks of their bodies are blasted away with heat or
radiation. A Rice University study in the Feb. 16 issue of Physical Review
Letters offers the first explanation: tiny blemishes crawl over the skin of
the damaged nanotubes, sewing up larger holes as they go.

Rice science news - Nanotube, heal thyself

Houston, TX | Posted on February 15th, 2007

"The shape and direction of this imperfection does not change, and it never
gets any larger," said lead researcher Boris Yakobson, professor of
mechanical engineering and materials science and of chemistry. "We were
amazed by it, but upon further study we found a good explanation. The atomic
irregularity acts as a kind of safety valve, allowing the nanotube to
release excess energy, in much the way that a valve allows steam to escape
from a kettle."

The research appears Feb. 16 issue of in Physical Review Letters.

Carbon nanotubes are hollow cylinders of pure carbon that measure about a
billionth of a meter, or one nanometer, across. They are much longer than
they are wide, akin in shape to 100-foot garden hose, and they're 100 times
stronger than steel at one-sixth the weight.

The carbon atoms in nanotubes are joined together in six-sided hexagons, so
when scientists sketch out the arrangement on paper, nanotubes look
something like a rolled up tube of chicken wire. Yakobson's "smart repair
machine" is a deformity, a blemish in this pattern. The blemish consists of
a five-sided pentagon joined to a seven-sided heptagon and contains a total
of ten atoms. Yakobson, who specializes in using computers to decipher the
atomic pecularities of materials, discovered several years ago that
mechanically stressed nanotubes - like those being pulled very hard from
both ends - are predisposed to develop these 5/7-defects due to the complex
interplay of thermodynamic forces at work in the nanotube.

In the latest study, Yakobson, research associate Feng Ding and students
examined the effects of other types of stress, including exposure to heat
and radiation. The tests confirmed the predisposition of nanotubes to
develop the 5/7 blemishes, and they revealed the blemishes' unexpected
healing powers.

"The 5/7-blemishes move across the surface of the nanotube like a steamship,
giving off puffs of carbon gas," said Ding. "In their wake, the skin of the
tube appears pristine, in its characteristic hexagonal arrangement."

Yakobson said the blemishes consume all larger defects, and chug along
indefinitely, rearranging atoms and healing the skin of the damaged
nanotubes. This explains how nanotubes retain their strength, even when
severely damaged. But the healing comes with a price.

"In their role as a safety valve, the 57-steamers give off energy and mass,
which is released as pairs of gaseous carbon atoms," Yakobson said. "Since
they never change shape or stop moving, they ever so slowly eat away the
surface of the nanotube, one pair of atoms at a time."

Yakobson said the 5/7-blemishes turn when they reach the end of the nanotube
and return in the opposite direction. In fact, there's only one thing that
can stop them: another 5/7 blemish. If two of the blemishes run headlong
into one other, they cancel each other out and disappear.

Research co-authors include graduate students Kun Jiao and Mingqi Wu.

The research was supported by the Office of Naval Research, the National
Science Foundation and the Robert A. Welch Foundation.

####

About Rice University
Rice University is consistently ranked one of America’s best teaching and
research universities. It is distinguished by its: size—2,850 undergraduates
and 1,950 graduate students; selectivity—10 applicants for each place in the
freshman class; resources—an undergraduate student-to-faculty ratio of
6-to-1, and the fifth largest endowment per student among American
universities; residential college system, which builds communities that are
both close-knit and diverse; and collaborative culture, which crosses
disciplines, integrates teaching and research, and intermingles
undergraduate and graduate work. Rice’s wooded campus is located in the
nation’s fourth largest city and on America’s South Coast.

For more information, please click here

Contacts:
Jade Boyd
713-348-6778

Copyright © Rice University

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:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Nanotubes/Buckyballs/Fullerenes

Programmable materials find strength in molecular repetition May 23rd, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

Unveiling the electron's motion in a carbon nanocoil: Development of a precise resistivity measurement system for quasi-one-dimensional nanomaterials using a focused ion beam May 16th, 2016

New research shows how silver could be the key to gold-standard flexible gadgets: Silver nanowires are an ideal material for current and future flexible touch-screen technologies May 13th, 2016

Discoveries

Fast, stretchy circuits could yield new wave of wearable electronics May 30th, 2016

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Materials/Metamaterials

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Revealing the nature of magnetic interactions in manganese oxide: New technique for probing local magnetic interactions confirms 'superexchange' model that explains how the material gets its long-range magnetic order May 25th, 2016

Diamonds closer to becoming ideal semiconductors: Researchers find new method for doping single crystals of diamond May 25th, 2016

Announcements

JPK’s NanoWizard AFM system is being used for cell studies in the Research Centre for Nanometer-scale Science & Advanced Materials at the Jagiellonian University in Krakow, Poland May 31st, 2016

Nanobiotix receives US$1m milestone payment from PharmaEngine: First patient injected with NBTXR3 in soft tissue sarcoma registration phase in Asia May 31st, 2016

GLOBALFOUNDRIES to Expand Presence in China with 300mm Fab in Chongqing: Company plans new manufacturing facility and additional design capabilities to serve customers in China May 31st, 2016

Nanobiotix establishes promising preclinical proof-of-concept in Immuno Oncology May 31st, 2016

Human Interest/Art

Scientists propose non-animal tools for assessing the toxicity of nanomaterials: Particle and Fibre Toxicology publishes recommendations from expert group meeting April 26th, 2016

Are humans the new supercomputer?Today, people of all backgrounds can contribute to solving serious scientific problems by playing computer games. A Danish research group has extended the limits of quantum physics calculations and simultaneously blurred the boundaries between mac April 14th, 2016

UCLA nanoscientists engage shoppers in fun conversations March 8th, 2016

Risk Analysis Publishes Non-Animal Strategy to Assess Nanomaterials February 24th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic