Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Self-Destructing Messages

'Disappearing' Nanoparticle Ink: A new writing medium can be tweaked to erase itself after a pre-determined length of time. Rafal Klajn
'Disappearing' Nanoparticle Ink: A new writing medium can be tweaked to erase itself after a pre-determined length of time. Rafal Klajn

Abstract:
Light-reactive coatings make metal nanoparticles into inks for self-erasing paper

Self-Destructing Messages

Evanston, IL | Posted on August 28th, 2009

Those who like to watch spy movies like "Mission Impossible" are familiar with the self-destructing messages that inform the secret agents of the details of their mission and then dissolve in a puff of smoke. In the real world, there is serious interest in materials that don't exactly destroy themselves, but that store texts or images for a predetermined amount of time. "Such re-writable ‘paper' would protect sensitive information," Bartosz A. Grzybowski of Northwestern University in Evanston (IL, USA) explains. "Imagine a meeting in the Pentagon where the classified materials self-erase when the meeting is over. No way to take them away and sell to terrorists." He and his team have developed a new concept that can be used to produce self-erasing pictures. In contrast to previous techniques, their method allows for multicolored pictures. As the researchers report in the journal Angewandte Chemie, their concept is based on an ‘ink' made of nanoscopic metal particles that clump together—in a reversible process—under the influence of light.

To make this new re-writable material, the researchers embed silver and/or gold nanoparticles in a thin film of an organic gel, which they then laminate. The films are bright red if they contain gold particles, and yellow if they contain silver. When these films are irradiated with UV light, the color of the film changes in the irradiated regions. The degree of difference depends on the duration of the irradiation. Gold-containing films change stepwise from red to pale blue; those containing sliver change from yellow to violet. Multicolored pictures can be produced if different areas are irradiated for different amounts of time. The resulting pictures are not permanent; they fade until they are completely erased.

How does it work? The trick lies in a special organic coating on the metal nanoparticles. Under UV light, certain groups of atoms in these molecules rearrange. This makes them more polar, which causes them to attract each other more strongly. The nanoparticles then prefer to clump together in large spherical aggregates. The color changes because the color of nanoscopic particles is dependent on the size of the aggregates they form. The size of the aggregates, in turn, depends on the duration of the UV irradiation. In this way, the color of the ink can be controlled.

The particle aggregates eventually break up into individual metal nanoparticles because the groups of atoms return to their original arrangements, and the color fades. The time it takes for the picture to be erased can be controlled by means of the exact composition of the coating. The erasure can be accelerated by irradiation with visible light or by heating.

Author: Bartosz A. Grzybowski, Northwestern University, Evanston (USA), dysa.northwestern.edu/

Title: Writing Self-Erasing Images using Metastable Nanoparticle "Inks"

Angewandte Chemie International Edition 2009, 48, No. 38, 7035-7039, doi: 10.1002/anie.200901119


####

About Angewandte Chemie International Edition
Wiley InterScience (www.interscience.wiley.com) provides access to over 3 million articles across nearly 1500 journals and 7000 Online Books and major reference works. It also holds industry leading databases such as The Cochrane Library, chemistry databases and the acclaimed Current Protocols laboratory manuals.

For more information, please click here

Contacts:
Journal Customer Services
John Wiley & Sons Inc
350 Main Street
Malden MA 02148
USA

Copyright © Angewandte Chemie International Edition

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

Speedy ion conduction in solid electrolytes clears road for advanced energy devices May 5th, 2016

Engineers create a better way to boil water -- with industrial, electronics applications May 5th, 2016

Clues on the path to a new lithium battery technology: Charging produces highly reactive singlet oxygen in lithium air batteries May 5th, 2016

Unique nano-capsules promise the targeted drug delivery: Russian scientists created unique nano-capsules for the targeted drug delivery May 5th, 2016

Possible Futures

Speedy ion conduction in solid electrolytes clears road for advanced energy devices May 5th, 2016

Engineers create a better way to boil water -- with industrial, electronics applications May 5th, 2016

Clues on the path to a new lithium battery technology: Charging produces highly reactive singlet oxygen in lithium air batteries May 5th, 2016

Unique nano-capsules promise the targeted drug delivery: Russian scientists created unique nano-capsules for the targeted drug delivery May 5th, 2016

Announcements

Speedy ion conduction in solid electrolytes clears road for advanced energy devices May 5th, 2016

Engineers create a better way to boil water -- with industrial, electronics applications May 5th, 2016

Clues on the path to a new lithium battery technology: Charging produces highly reactive singlet oxygen in lithium air batteries May 5th, 2016

Unique nano-capsules promise the targeted drug delivery: Russian scientists created unique nano-capsules for the targeted drug delivery May 5th, 2016

Homeland Security

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Nanoporous material's strange "breathing" behavior April 7th, 2016

Sniffing out a dangerous vapor: University of Utah engineers develop material that can sense fuel leaks and fuel-based explosives March 28th, 2016

Detecting and identifying explosives with single test December 10th, 2015

Military

New tool allows scientists to visualize 'nanoscale' processes May 4th, 2016

Making invisible physics visible: The Jayich Lab has created a new sensor technology that captures nanoscale images with high spatial resolution and sensitivity May 2nd, 2016

Nanograft seeded with 3 cell types promotes blood vessel formation to speed wound healing April 27th, 2016

The light stuff: A brand-new way to produce electron spin currents - Colorado State University physicists are the first to demonstrate using non-polarized light to produce a spin voltage in a metal April 26th, 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