Featured Research

from universities, journals, and other organizations

Crystal defect shown to be key to making hollow nanotubes

Date:
April 22, 2010
Source:
University of Wisconsin-Madison
Summary:
Scientists have no problem making a menagerie of nanometer-sized objects -- wires, tubes, belts, and even tree-like structures. What they sometimes have been unable to do is explain precisely how those objects form in the vapor and liquid cauldrons in which they are made.

Scientists have no problem making a menagerie of nanometer-sized objects -- wires, tubes, belts, and even tree-like structures. What they sometimes have been unable to do is explain precisely how those objects form in the vapor and liquid cauldrons in which they are made.

Now a team led by University of Wisconsin-Madison chemist Song Jin, writing in the journal Science, shows that a simple crystal defect known as a "screw dislocation" drives the growth of hollow zinc oxide nanotubes just a few millionths of a centimeter thick.

The finding is important because it provides new insight into the processes that guide the formation of the smallest manufactured structures, a significant challenge in nanoscience and nanotechnology. "We think that this work provides a general theoretical framework for controlling nanowire or nanotube growth without using metal catalysts that can be generally applicable to many materials," says Jin, a UW-Madison professor of chemistry.

Such materials and the Lilliputian structures scientists sculpt have already found broad applications in such things as electronics, solar power, battery and laser technology, and chemical and biological sensing. By further expanding the theory of how the tiny structures form, it should now be possible for scientists to develop new methods to mass produce nano-sized objects using a variety of different materials.

The method described by Jin and his colleagues depends on what scientists call a screw dislocation. Dislocations are fundamental to the growth and characteristics of all crystalline materials. As their name implies, these defects prompt the creation of spiral steps on an otherwise flawless crystal face. As atoms alight on the crystal surface, they form a structure strikingly similar in appearance to the spiral ramps of multistory parking structures. In earlier work, Jin and his research group showed that screw dislocations drive the growth of one-dimensional nanowire structures that looked like tiny pine trees. That, says Jin, was a critical clue to understanding the kinetics of spontaneous nanotube growth.

The key to understanding how to harness the defect to make nanostructures in a rational way, Jin explains, is knowing that as atoms collect on a surface of a dislocation spiral, strain associated with screw dislocations builds up in the tiny structures they create.

It turns out that "making the structure hollow and making it twist are two good ways of relieving such strain and stress," Jin explains. "In some cases, the large screw dislocation strain energy contained within the nanomaterial dictates that the material hollow out its center around the dislocation, thus resulting in the spontaneous formation of nanotubes."

The phenomenon described in the new Wisconsin work differs in significant ways from traditional mechanisms of making hollow nanostructures. Scientists now use templates to "mold" nanotubes or, alternatively, a diffusion process to convert one material into another with a hollow core. Carbon nanotubes are made, essentially, by rolling up a single honeycomb-patterned layer of carbon atoms.

The phenomena described by the Wisconsin team, Jin adds, should apply to materials beyond zinc oxide: "The understanding of the formation of nanotubes will certainly help us to understand related phenomena in other materials."

Refined, the new knowledge could ultimately be turned to the large scale, low cost production of nanomaterials for a wide range of applications. Most promising, says Jin, is the area of renewable energy where large amounts of such materials can be deployed to convert sunlight to electricity, and provide new raw materials for battery electrodes and thermoelectric devices.

The new work in Jin's lab was carried out by graduate students Stephen A. Morin and Matthew J. Bierman, with assistance from a former undergraduate student Jonathan Tong, all of UW-Madison. The work was funded primarily by National Science Foundation.


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. The original article was written by Terry Devitt. Note: Materials may be edited for content and length.


Journal Reference:

  1. Stephen A. Morin, Matthew J. Bierman, Jonathan Tong, and Song Jin. Mechanism and Kinetics of Spontaneous Nanotube Growth Driven by Screw Dislocations. Science, 2010; 328 (5977): 476 DOI: 10.1126/science.1182977

Cite This Page:

University of Wisconsin-Madison. "Crystal defect shown to be key to making hollow nanotubes." ScienceDaily. ScienceDaily, 22 April 2010. <www.sciencedaily.com/releases/2010/04/100422153802.htm>.
University of Wisconsin-Madison. (2010, April 22). Crystal defect shown to be key to making hollow nanotubes. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2010/04/100422153802.htm
University of Wisconsin-Madison. "Crystal defect shown to be key to making hollow nanotubes." ScienceDaily. www.sciencedaily.com/releases/2010/04/100422153802.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins