Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Light twists rigid structures in unexpected nanotech finding

After 72 hours of exposure to ambient light, strands of nanoparticles twisted and bunched together. Credit: Nicholas Kotov
After 72 hours of exposure to ambient light, strands of nanoparticles twisted and bunched together. Credit: Nicholas Kotov

Abstract:
In findings that took the experimenters three years to believe, University of Michigan engineers and their collaborators have demonstrated that light itself can twist ribbons of nanoparticles.

The results are published in the current edition of Science.

Light twists rigid structures in unexpected nanotech finding

Ann Arbor, MI | Posted on March 17th, 2010

Matter readily bends and twists light. That's the mechanism behind optical lenses and polarizing 3-D movie glasses. But the opposite interaction has rarely been observed, said Nicholas Kotov, principal investigator on the project. Kotov is a professor in the departments of Chemical Engineering, Biomedical Engineering and Materials Science and Engineering.

While light has been known to affect matter on the molecular scale—bending or twisting molecules a few nanometers in size—it has not been observed causing such drastic mechanical twisting to larger particles. The nanoparticle ribbons in this study were between one and four micrometers long. A micrometer is one-millionth of a meter.

"I didn't believe it at the beginning," Kotov said. "To be honest, it took us three and a half years to really figure out how photons of light can lead to such a remarkable change in rigid structures a thousand times bigger than molecules."

Kotov and his colleagues had set out in this study to create "superchiral" particles—spirals of nano-scale mixed metals that could theoretically focus visible light to specks smaller than its wavelength. Materials with this unique "negative refractive index" could be capable of producing Klingon-like invisibility cloaks, said Sharon Glotzer, a professor in the departments of Chemical Engineering and Materials Science and Engineering who was also involved in the experiments. The twisted nanoparticle ribbons are likely to lead to the superchiral materials, the professors say.

To begin the experiment, the researchers dispersed nanoparticles of cadmium telluride in a water-based solution. They checked on them intermittently with powerful microscopes. After about 24 hours under light, the nanoparticles had assembled themselves into flat ribbons. After 72 hours, they had twisted and bunched together in the process.

But when the nanoparticles were left in the dark, distinct, long, straight ribbons formed.

"We discovered that if we make flat ribbons in the dark and then illuminate them, we see a gradual twisting, twisting that increases as we shine more light," Kotov said. "This is very unusual in many ways."

The light twists the ribbons by causing a stronger repulsion between nanoparticles in them.

"The twisted ribbon is a new shape in nanotechnology," Kotov said. "Besides superchiral materials, he envisions clever applications for the shape and the technique used to create I it. Sudhanshu Srivastava, a postdoctoral researcher in his lab, is trying to make the spirals rotate."

"He's making very small propellers to move through fluid—nanoscale submarines, if you will," Kotov said. "You often see this motif of twisted structures in mobility organs of bacteria and cells."

The nanoscale submarines could conceivably be used for drug-delivery and in microfluidic systems that mimic the body for experiments.

This newly-discovered twisting effect could also lead to microelectromechanical systems that are controlled by light. And it could be utilized in lithography, or microchip production.

Glotzer and Aaron Santos, a postdoctoral researcher in her lab, performed computer simulations that helped Kotov and his team better understand how the ribbons form. The simulations showed that under certain circumstances, the complex combination of forces between the tetrahedrally-shaped nanoparticles could conspire to produce ribbons of just the width observed in the experiments. A tetrahedron is a pyramid-shaped, three-dimensional polyhedron.

"The precise balance of forces leading to the self-assembly of ribbons is very revealing," Glotzer said. "It could be used to stabilize other nanostructures made of non-spherical particles. It's all about how the particles want to pack themselves."

Other collaborators include researchers from the University of Leeds in the UK, Chungju National University in Korea, Argonne National Laboratory, Pusan National University in Korea and Jiangnan University in China.

The paper is titled Light-Controlled Self-Assembly of Semiconductor Nanoparticles into Twisted Ribbons. The research is funded by the Air Force Office of Scientific Research, the Korea Science and Engineering Foundation and the U.S. Department of Energy.

####

About University of Michigan College of Engineering
Michigan Engineering: The University of Michigan College of Engineering is ranked among the top engineering schools in the country. At $160 million annually, its engineering research budget is one of largest of any public university. Michigan Engineering is home to 11 academic departments and a National Science Foundation Engineering Research Center. The college plays a leading role in the Michigan Memorial Phoenix Energy Institute and hosts the world class Lurie Nanofabrication Facility. Michigan Engineering's premier scholarship, international scale and multidisciplinary scope combine to create The Michigan Difference.

For more information, please click here

Contacts:
Nicole Casal Moore
Phone: (734) 647-7087

Copyright © University of Michigan College of Engineering

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

News and information

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Graphene is strong, but is it tough? Berkeley Lab scientists find that polycrystalline graphene is not very resistant to fracture February 7th, 2016

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Researchers discover new phase of boron nitride and a new way to create pure c-BN February 5th, 2016

PEN Inc. Announces Strategy to Broaden Clarity Branded Products Business February 4th, 2016

Microfluidics/Nanofluidics

Scientists have shown how to make a low-cost yet high precision glass nanoengraving: In a joint study, scientists have developed a mechanism of laser deposition of patterns on glass with a resolution of 1000 times lower than the width of a human hair January 21st, 2016

Nanoworld 'snow blowers' carve straight channels in semiconductor surfaces: NIST, IBM researchers report important addition to toolkit of 'self-assembly' methods eyed for making useful devices December 28th, 2015

New device uses carbon nanotubes to snag molecules: Nanotube “forest” in a microfluidic channel may help detect rare proteins and viruses December 21st, 2015

A cheap, disposable device for diagnosing disease December 2nd, 2015

Govt.-Legislation/Regulation/Funding/Policy

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Possible Futures

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

Host-guest nanowires for efficient water splitting and solar energy storage February 7th, 2016

Graphene is strong, but is it tough? Berkeley Lab scientists find that polycrystalline graphene is not very resistant to fracture February 7th, 2016

Scientists take key step toward custom-made nanoscale chemical factories: Berkeley Lab researchers part of team that creates new function in tiny protein shell structures February 6th, 2016

Academic/Education

COD Grad Begins Postdoctoral Fellow at Harvard University: Marsela Jorgolli's Passion for Physics Has Led to a Decade of Academic Research That Continues at Harvard University as a Postdoctoral Fellow February 2nd, 2016

Heriot-Watt's Institute of Photonics & Quantum Sciences uses the Deben Microtest 2 kN tensile stage to characterise ceramics and engineering plastics January 21st, 2016

Multiple uses for the JPK NanoWizard AFM system in the Smart Interfaces in Environmental Nanotechnology Group at the University of Illinois at Urbana-Champaign January 20th, 2016

BioSolar Extends Research Agreement With UCSB for Next Phase of Its Super Battery Technology: Development Effort to Continue Under the Supervision of Nobel Laureate, Dr. Alan Heeger January 13th, 2016

Chip Technology

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

The iron stepping stones to better wearable tech without semiconductors February 8th, 2016

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Scientists guide gold nanoparticles to form 'diamond' superlattices: DNA scaffolds cage and coax nanoparticles into position to form crystalline arrangements that mimic the atomic structure of diamond February 4th, 2016

Nanomedicine

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

UTHealth research looks at nanotechnology to help prevent preterm birth February 7th, 2016

Scientists take key step toward custom-made nanoscale chemical factories: Berkeley Lab researchers part of team that creates new function in tiny protein shell structures February 6th, 2016

Hepatitis virus-like particles as potential cancer treatment February 5th, 2016

Announcements

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Leading bugs to the death chamber: A kinder face of cholesterol February 8th, 2016

From allergens to anodes: Pollen derived battery electrodes February 8th, 2016

Photonics/Optics/Lasers

Organic crystals allow creating flexible electronic devices: The researchers from the Faculty of Physics of the Moscow State University have grown organic crystals that allow creating flexible electronic devices February 5th, 2016

Scientists guide gold nanoparticles to form 'diamond' superlattices: DNA scaffolds cage and coax nanoparticles into position to form crystalline arrangements that mimic the atomic structure of diamond February 4th, 2016

Nature Materials: Smallest lattice structure worldwide: 3-D lattice with glassy carbon struts and braces of less than 200 nm in diameter has higher specific strength than most solids February 3rd, 2016

Silicon-based metamaterials could bring photonic circuits February 1st, 2016

Research partnerships

Scientists take key step toward custom-made nanoscale chemical factories: Berkeley Lab researchers part of team that creates new function in tiny protein shell structures February 6th, 2016

Polar vortices observed in ferroelectric: New state of matter holds promise for ultracompact data storage and processing February 4th, 2016

Spin dynamics in an atomically thin semi-conductor February 1st, 2016

Graphene shown to safely interact with neurons in the brain January 31st, 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