Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chemists learn to build curved structures with nanoscale building blocks

16.01.2004


The natural world is full of curves and three dimensions, but the ability to deliberately and rationally construct such complex structures using nanoscale building blocks has eluded nanotechnologists who are eager to add curved structures to their toolbox.



Now a team of Northwestern University chemists report they have discovered ways to construct nanoscale building blocks that assemble into flat or curved structures with a high level of predictability, depending on the architecture and composition of the building blocks. The results will be published in the Jan. 16 issue of the journal Science.

Using hybrid nanorods consisting of segments of gold and conducting polymers as their building blocks, the researchers created a number of unusual structures, including bundles, sheets and tubes of varying diameters. The extraordinary control that they were able to demonstrate over the process holds promise for building new and powerful drug delivery systems, electronic circuits, catalysts and light-harvesting materials.


"We are trying to mimic life itself," said Chad A. Mirkin, director of Northwestern’s Institute for Nanotechnology, who led the research team. "Much like proteins which must fold into complex structures in order to function properly, we have designed new materials that also form complex structures through the process of self-assembly."

Mirkin and his team made the different structures by varying the diameter of the gold-polymer rods or adjusting the ratio of polymer segment to gold segment in the rods. Both methods should enable researchers to design structures with interesting electronic and optical properties.

"We also discovered that the alumina template we used to build the rods initially is essential in guiding the assembly process," said Mirkin, also George B. Rathmann Professor of Chemistry. "Without the orientation the template provides, the rods do not form bundles, sheets or tubes."

The nanorods were made by the sequential deposition of gold and conducting polymer into the pores of an aluminum template. After the gold-polymer rods were synthesized, the template was dissolved, leaving the rods parallel to one another, gold end to gold end and polymer end to polymer end. The strong interactions between the polymer ends built stress, causing curves to form.

In a subsequent experiment, the researchers observed that self-assembly did not take place when the rods were randomly dispersed in solution.

"The research clearly shows that some unnatural building blocks, such as the gold-polymer rods, need assistance in order to form higher-ordered structures," said Mirkin. "This means that when we work with building blocks that are larger than molecules but smaller than macroscopic objects, we should consider building materials in a completely new way -- by using templates to help guide the assembly process and reduce the large number of assembly pathways potentially available to the building blocks."


In addition to Mirkin, other authors on the Science paper are Sungho Park (lead author), Jung-Hyurk Lim and Sung-Wook Chung, all from Northwestern University. The research was supported by the National Science Foundation and the U.S. Air Force Office of Scientific Research.

Megan Fellman | EurekAlert!
Further information:
http://www.nwu.edu/

More articles from Life Sciences:

nachricht Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

25.09.2017 | Trade Fair News

Highest-energy cosmic rays have extragalactic origin

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>