Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Organizing dumbbells for nanotech devices

15.05.2006


Bridging the gap between nanoscience and nanotechnology



A team of chemists from France, Italy, Spain, the UK, and the US are working together to bridge the gap between nanoscience and nanotechnology. They have now devised a method that could allow them to organize tiny molecular machines on a surface and so build devices that pack in thousands of times as many switching units, for instance, than is possible with a conventional silicon chip.

Chemist Fraser Stoddart, now at the University of California Los Angeles, and his co-workers have designed and made numerous molecules based on hanging ring-shaped molecules on other chain-like molecules and loops. By incorporating functional chemical groups along the length of the chain or around these loops, they have shown that it is possible to make the molecular beads switch between these various functional groups using heat, light, or electricity. The ultimate aim of creating such molecular-scale devices is to use them as switching units or logic gates in a future computer based on molecules instead of silicon chips.


Before that will be possible, however, the nanoscientists must find a way to organize arrays of these molecules on a surface so that input and output connections can be made between the molecules and the outside world.

Stoddart and colleague Alberto Credi of the University of Bologna, Italy, and co-workers at the University of Birmingham, UK, the University Paul Sabatier, Toulouse, France, and the University of Valencia in Spain recognize that in order to exploit their molecular machines they will need to find a way to organize them at interfaces, deposit them on functional surfaces, or immobilize them into membranes or porous materials. This will allow the molecular machines to work together and to be "addressed" on the nanometer scale. The researchers believe that modifying the surface of an electrode to incorporate an organized layer of molecular machines could be the key to success.

The team reports in the current issue of Advanced Materials how they have recently succeeded in applying an incredibly thin layer, just a few molecules thick, of a particular molecular machine to a glass surface. The molecular machine in question is a switchable rotaxane--a ring-shaped molecule held on a short chain by two blocking groups, making it resemble a dumbbell with a collar around the handle.

A special technique was used to make thin layers of this dumbbell-shaped component in solution on a glass slide coated with ITO (indium tin oxide). By using two solutions--one containing the dumbbells and the other a soapy surfactant compound--the researchers were able to force the molecules to organize themselves because of electrostatic repulsion and attraction between the surfactant, the molecules, and the surface, until ultimately they became attached with the same orientation to the ITO layer on the glass slide.

The researchers then tested their thin layers of dumbbell molecules to see whether they would work as planned. They found that the thin film exhibited a reversible switching behavior when exposed cyclically to an acid and then a base. This, they explain, demonstrates that the thin film is capable of transducing a chemical input signal--the acid-base--into an electrical output signal. This bodes well for interfacing other molecular machines in a similar way.

There is, however, a puzzle that remains unsolved in this particular experiment. The team’s other molecular machines have an obvious switching capacity between two functional units on the chain or loop, as mentioned previously. However, there are no functional units on the dumbbell, so there is actually nothing to switch. The researchers are still puzzling over how the switching they observe takes place in the dumbbell molecules.

Ultimately, control using a light source or electricity will be required before such layers will be useful in the development of molecular computers, but this first small step to organizing molecular machines could lead to the required breakthrough.

Ute Schnebel | EurekAlert!
Further information:
http://www.wiley-vch.de

More articles from Materials Sciences:

nachricht Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester

nachricht CWRU directly measures how perovskite solar films efficiently convert light to power
12.01.2017 | Case Western Reserve 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: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Satellite-based Laser Measurement Technology against Climate Change

17.01.2017 | Machine Engineering

Studying fundamental particles in materials

17.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>