Wagon wheels developed using nanotechnology techniques could be used to make improved food packaging materials, according to a study published by German scientists.
Nanotechnology is a method of controlling matter at near-atomic scales to produce unique or enhanced materials, products and devices. With a different nanostructure, the gas and water vapor permeability of plastics can be engineered to preserve fruit, vegetables, beverages, wine and other food.
With the use of nanoparticles, bottles and packaging can be made lighter and stronger, with better thermal performance and less gas absorption. These properties can extend the shelf life of products, as well as lower the transportation costs involved in shipping food.
In a paper, Sigurd Högerof Universität Bonn in Germany said he and his research team managed to use nanotechnology to synthesise a molecule shaped like a wagon wheel.
Scanning tunneling microscope images published with the article in the journal Angewandte Chemie depict giant molecules with a diameter of seven nm. The molecule's "hub", "spokes", and "rim" of the highly symmetric structure are clearly recognisable in the images, they stated.
Two-dimensional particles, such as inorganic alumina platelets, are used as fillers for plastics because they impart excellent mechanical properties to these materials, they stated.
Nanocomposites made of alumina platelets and polymers are thus extraordinarily rigid, strong, and thermally stable materials, they stated.
"The barrier properties of plastics with respect to liquids and gasses, such as oxygen, could be improved by the addition of nanoscopic platelets," the paper stated. "This would be useful for applications such as food packaging, and makes less expensive, more environmentally friendly plastics accessible."
To better understand the way in which the platelets work, several researchers have been working with synthetic alumina platelets.
Some are interested in the use of large organic molecules in the form of rigid disks. Such disks can be produced with uniform shapes and sizes and their chemical properties can be adjusted as needed by the attachment of additional functional groups.
"Until now, organic molecular disks could not be made as large as the inorganic originals they are intended to imitate," the researchers stated.
Now Högerof's team from the universities of Bonn and Leuven claim to have jumped this hurdle by successfully synthesing very large wheel-shaped molecules.
In the next step, the researchers will attempt to grow these little wheels bit by bit by adding more building blocks onto the rim. The development should result in structures resembling a spider web, they stated.
Worldwide sales of nanotechnology-related products approached the $1bn (€739m) mark in 2005, with packaging for the food industry worth as much as $30bn (€22bn), according to a study by Helmut Kaiser.
The consultancy estimates that nanotechnology will change 25 per cent of the food packaging market, currently worth $100bn (€74bn), in the decade to follow.
The surge in demand is expected to be driven by new applications for the technology.
The new product development has driven sales in nanotechnology products from $150m (€111m) in 2002, to $860 (€635m)i n 2004, with total demand at $980m (€724m) in 2006, according to the study.
According to Helmut Kairser, packaging will increasingly become a service trying to meet multiple functions.
Author: Sigurd Höger, Universität Bonn (Germany), http://www.chemie.uni-bonn.de/oc/ak_ho/
Title: Molecularly Defined Shape-Persistent 2D Oligomers: The Covalent-Template Approach to Molecular Spoked Wheels
Angewandte Chemie International Edition, doi: 10.1002/anie.200701614.