The future of packaging could come down to particles just one billionth of a metre in diameter.
Nanoparticles are increasingly being combined with more traditional packaging materials, from plastics to paper. They can be used to change the physical properties of that material or, in some cases, form an indicator or display. The tiny particles measure less than 100 nanometres across, beyond which point their properties tend to change, says Andy Garland, head of information at the Institute of Nanotechnology in Stirling.
Already, nanotechnology is being used to make film and other plastics structures far denser, maximising the tensile strength and the effectiveness of the gas barrier. According to Garland, US brewer Coors has combined nanoparticles with the polyethylene terephthalate (PET) used in its beer bottles. "If you integrate nanoparticles into the material, the particles form such a dense matrix that it is extremely difficult for oxygen to penetrate," he explains.
Potentially, packs using the technology can be made much lighter. "But in most cases," Garland warns, "the cost is still prohibitive." Particles may be derived from materials such as ceramics or clays, and can be integrated into the mass of the pack or, in some cases, applied as a coating.
One particular technology to which the "prohibitive" price tag is still attached is nanotubes. Though not necessarily destined for packaging applications, this matrix of cylindrical structures forms a mass which is 100 times stronger than steel, and one sixth of the weight.
The cost barrier may first be overcome in the visible display area, where one Irish company is already working with Japanese partners to produce polymer light-emitting diodes -- effectively flexible electronic diplays. Says Garland: "Nanotechnology will really impact with functions such as freshness indicators, anti-counterfeiting systems and tamper-proofing."
According to Garland, Professor Andrew Mills of the University of Strathclyde is among those who have been working with nanocrystalline materials for applications including freshness indicators and oxygen scavengers.
Garland and Mills will be speakers at Pira International's Flexible Packaging 2004 conference, in London on December 9-10.