Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bath toys show strength in numbers

22.02.2002


Floating crescents could self-assemble into circuits


Miniature floating craft can be programmed to move and assemble in complex ways.

Harvard chemists are playing with bath toys. Floating bubble-powered craft designed to attract and repel one another, are helping them model the machinations of groups such as foraging ants, nest-building termites or schools of fish1.

Group dynamics are not always obvious from individuals’ behaviour, but emerge from their interactions. Computer models can simulate such processes. However George Whitesides and his coworkers in Cambridge, Massachusetts hope that using real experimental systems to elicit emergent properties will have a crucial advantage.



They want to exploit the self-organization inherent in their toys’ collective motions. For instance to assemble machines or electronic circuits from components that automatically swim into position.

Whitesides’ team made thin half-moons of water-repelling plastic about the size of a little fingernail. When two discs get near enough on a watery surface their edges attract each other and stick loosely together. Chemically treating some of the plate edges so that they aren’t water-repellent suppresses the attraction. The team tailored the discs to attract and adhere along some edges but not others.

To make these plates self-propel, the researchers fixed a small piece of platinum-covered glass underneath one corner. When they set the discs adrift on the surface of hydrogen peroxide solution, the platinum acted as a catalyst, breaking down the hydrogen peroxide into oxygen gas. The bubbles released propelled the plates over the water surface at speeds of up to 2 cm per second for several hours.

The plates thus derive energy for their motion from their environment instead of carrying a fuel tank. Varying the catalysts or the peroxide concentration varies their speed. The asymmetric position of the platinum engine under each semicircular plate drives them into circulating movements. Which way they twirl depends on which side the engine sits.

If two plates that rotate in the same direction stick together, the assembly also rotates in that direction. If two oppositely rotating plates unite, their tendencies cancel out, and the pair moves more or less in a straight line.

So even in this very simple system a new property - straight-line motion - appears when the rotating individuals get together. "We believe", say the researchers, "that assemblies of tens or hundreds of components may show substantially more complex behaviours".

References
  1. Ismagilov, R. F., Schwartz, A., Bowden, N. & Whitesides, G. M. Autonomous movement and self-assembly. Angewandte Chemie International Edition, 41, 652 - 654, (2002).


PHILIP BALL | Nature News Service

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life 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

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>