Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Nanowires highly 'anelastic,' research shows


Researchers from Brown University and North Carolina State University have found that nanowires made of zinc oxide are highly anelastic, meaning they return to shape slowly after being bent, rather that snapping right back. The findings, published in the journal Nature Nantechnology, add one more to the growing list of interesting properties found in nanoscale wires, tiny strands thousands of times thinner than a human hair.

"What's surprising here is the magnitude of the effect," said Huajian Gao, the Walter H. Annenberg Professor of Engineering and a coauthor of a new paper describing the research. "Anelasticity is present but negligible in many macroscale materials, but becomes prominent at the nanoscale. We show an anelastic effect in nanowires that is four orders of magnitude larger than what is observed in even the most anelastic bulk materials."

Zinc oxide nanowires return to shape slowly after being bent, new research from Brown and NC State shows. That property, called anelasticity, suggests that nanowires might be good in applications that require absorption of shocks or vibrations.

Credit: Zhu lab / NC State

The findings are significant in part because anelastic materials are good absorbers of kinetic energy. These results suggest that nanowires could be useful in damping shocks and vibrations in a wide variety of applications.

"During the last decade, zinc oxide nanowire has been recognized as one of the most important nanomaterials with a broad range of applications such as mechanical energy harvesting, solar cells, sensors and actuators," Gao said. "Our discovery of giant anelasticity and high energy dissipation in zinc oxide nanowires adds a new dimension to their functionality."

The experiments for the study were done in the lab of Yong Zhu, an associate professor of mechanical and aerospace engineering at NC State. Zhu and his colleagues used a delicate apparatus to bend nanowires under a scanning electron microscope.

The work showed that, after the bending strain was released, the wires returned to about 80 percent of their original shape quickly. But they recovered the rest of their original shape much more slowly, over the course of up to 20 or 30 minutes. That is a far more prominent anelastic effect than is common at the macroscale.

To understand why the effect is so prominent, Zhu and his team worked with Gao's lab at Brown, which specializes in theoretical modeling of nanoscale systems. The model that Gao and his colleagues developed suggests that the anelasticity is a result of impurities in the wires' crystal lattice.

Lattice impurities come in two forms. There are vacancies, where atoms are missing from the lattice; and there are interstitials, where the lattice has extra atoms. When a wire is bent to form an arch, there's higher compressive strain on the underside of the arch compared to the upper side. The compression pushes interstitial atoms toward the outside edge, and draws the vacancies toward the inside. When the strain is released, those impurities migrate back to where they started.

That migration takes a bit of time, which is why the wire returns to shape slowly. Because nanowires are so small, the impurities need only travel a short distance to generate a perceptible anelastic effect, which is why the effect is so much more pronounced at the nanoscale compared to the macroscale.

To further test whether the anelasticity was rooted in impurities, the team tested wires made from a different material--silicon doped with boron impurities. Like the zinc oxide nanowires, the doped silicon also proved to be anelastic.

The findings suggest that anelasticity is likely a common property of single-crystal nanowires. "One reviewer [of our paper] commented that this is a new important page in the book on mechanics of nanostructures," Zhu said. "The factors that favor anelasticity, such as high strain gradient, short diffusion distance and large diffusivity of point defects, are all prominently present in nanowires".


Other authors on the paper were Guangming Cheng, Qingquan Qin, Jing Li, Feng Xu and Elizabeth C. Dickey from NC State, and Chunyang Miao and Hamed Haftbaradaran from Brown.

The research was supported by the National Science Foundation.

Kevin Stacey | EurekAlert!

More articles from Materials Sciences:

nachricht From ancient fossils to future cars
21.10.2016 | University of California - Riverside

nachricht Study explains strength gap between graphene, carbon fiber
20.10.2016 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>