Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

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

The mysterious 'action at a distance' between liquid containers November 26th, 2014

'Giant' charge density disturbances discovered in nanomaterials: Juelich researchers amplify Friedel oscillations in thin metallic films November 26th, 2014

Vegetable oil ingredient key to destroying gastric disease bacteria: In mice, therapeutic nanoparticles dampen H. pylori bacteria and inflammation that lead to ulcers and gastric cancer November 25th, 2014

Research yields material made of single-atom layers that snap together like Legos November 25th, 2014

Possible Futures

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Researchers discern the shapes of high-order Brownian motions November 17th, 2014

VDMA Electronics Production Equipment: Growth track for 2014 and 2015 confirmed: Business climate survey shows robust industry sector November 14th, 2014

Open Materials Development Will Be Key for HP's Success in 3D Printing: HP can make a big splash in 3D printing, but it needs to shore up technology claims and avoid the temptation of the razor/razor blade business model in order to flourish November 11th, 2014

Announcements

The mysterious 'action at a distance' between liquid containers November 26th, 2014

'Giant' charge density disturbances discovered in nanomaterials: Juelich researchers amplify Friedel oscillations in thin metallic films November 26th, 2014

Vegetable oil ingredient key to destroying gastric disease bacteria: In mice, therapeutic nanoparticles dampen H. pylori bacteria and inflammation that lead to ulcers and gastric cancer November 25th, 2014

Research yields material made of single-atom layers that snap together like Legos November 25th, 2014

Homeland Security

Better bomb-sniffing technology: University of Utah engineers develop material for better detectors November 4th, 2014

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

NanoTechnology for Defense (NT4D) October 22nd, 2014

UT Arlington researchers develop transparent nanoscintillators for radiation detection for medical safety and homeland security September 29th, 2014

Military

NRL Scientists Discover Novel Metamaterial Properties within Hexagonal Boron Nitride November 20th, 2014

Two sensors in one: Nanoparticles that enable both MRI and fluorescent imaging could monitor cancer, other diseases November 18th, 2014

Researchers create & control spin waves, lifting prospects for enhanced info processing November 17th, 2014

Penn engineers efficiently 'mix' light at the nanoscale November 17th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE