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 Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>