Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetic Chameleons

17.03.2011
New displays that change color under the influence of magnets

Chinese researchers have created microscopic capsules that change color when a magnetic field is applied. When the capsules are collected into an array, magnetic fields can be used to create colored patterns on an extremely small scale.


Many animals use tiny physical changes at their skin or surface to alter their color. Chameleons do this by pumping slightly different amount of dye into the surface of their skins. Other animals, such as some beetles, fish and birds, have special arrays of light-reflecting cells that are moved apart very slightly by the injection or removal of a fluid, or by tiny stretching of their skin. These nanometer changes in spacing are enough to change the wavelength of light that is reflected and hence the color that we see.

Scientists have been able to replicate this effect to some extent using regular clusters of tiny spheres known as colloidal crystals. The spacing between the centres of the spheres determines the wavelength of light that is reflected and, hence the color of the crystal. Simple actions such as adding fluid (as described above) or swelling the size of the particles have been used to change the color.

If the spheres used are magnetic, then a magnetic field can be used to control the spacing between them, and, of course, the color. This phenomenon has been shown previously, but stable systems were not created and the color seen was very dependent on viewing angle.

Now, as described in the journal Advanced Functional Materials, Zhongze Gu and coworkers at the Southeast University in Nanjing have created stable droplets of particles whose color can be tuned through a wide range and which does not depend on where the viewer stands.

Their breakthrough was to encapsulate clusters of magnetic spheres in a liquid within tiny, transparent resin beads. The beads are highly uniform and could be used as individual pixels in a display. Applying different magnetic fields causes the spheres within the capsules to move further apart or closer together, resulting in different colors. The picture shows the effect of applying different magnetic fields.

Another clever idea of Gu and his team was to use automated technology to create the capsules. Uniform sizes and composition are required if such materials are to be used as displays, and this was achieved by using microfluidic techniques, where reactions occur continuously as ingredients travel along the narrow channels of a very small-scale reactor. Tuning the flow rates of various reactants easily controls the capsulesf size, shell thickness and shape.

The scientists are proud of their work and imagine that it could be adapted to be used with electronic magnetic fields, using the full potential of the tiny scale of the microcapsules and leading to gmore complex and interesting patterns.h

C. Zhu, W. Y. Xu, L. S. Chen, W. D. Zhang, H. Xu, and Z. Z. Gu, gMagnetochromatic Microcapsule Array for Displayh, Adv. Funct. Mater. 2011; DOI: 10.1002:adfm.201002296.

Contact:
Prof. Zhongze Gu
State Key Laboratory of Bioelectronics
Sipailou 2, Nanjing, P. R. China
EmailFgu@seu.edu.cn
Tel/Fax: +86-25-83795635

Carmen Teutsch | Wiley-VCH
Further information:
http://www.wiley-vch.de
http://www.lmbe.seu.edu.cn/~guzhz/English/Eindex.htm

More articles from Materials Sciences:

nachricht Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State 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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>