From nano to atto, thinking small is big business
Once, the vast majority of researchers and engineers concerned themselves with processes and systems that operated on a large scale -- the design of rockets, controlling cancer cells and tweaking chem...
Once, the vast majority of researchers and engineers concerned themselves with processes and systems that operated on a large scale — the design of rockets, controlling cancer cells and tweaking chemical reactions that took place in test tubes and reactors. Today, whether the subject is microelectronics, splicing bits of genetic material or tiny loops of sub-atomic strings vibrating in unseen dimensions of space, most interest, and research funding, is directed toward efforts to probe and manipulate the exceedingly small.
With the development of the science of nanotechnology, the trend of operating and engineering at extremely small scales is revolutionizing material and polymer science, the effects of which are just beginning to trickle into the plastics industry.
As with the story of any new technology, there is a “gee-whiz” side and a more sobering assessment. The gee-whiz side of nanotechnology is so rich it has already worked itself into the public’s imagination in form of Michael Crichton’s novel “Prey” in which tiny, self-replicating robots begin to gobble up the earth.
A nanometre is a billionth of a metre, about the length of 10 hydrogen atoms. The particle sizes of the nano-fillers used in R&D and commercial plastics programs (e.g. layered silica, nano-talcs, carbon nanotubes and graphite platlets) are in the range of 10 to 100 nm. The principle behind nano-fillers is that as a particle gets smaller, the ratio between its surface area and its volume rises. Increased surface area means increased reactivity and, sure enough, researchers have found that nanofillers can deliver increased performance — tensile strength, modulus, etc. — at lower fill levels. This could be a boost for plastic in high performance applications such as automotive where designers are always questing to increase performance and lower weight.
Further afield, NanoSonic, a nanotechnology company based in the U.S., has created a metallic rubber which flexes and stretches like rubber but conducts electricity like a metal. General Electric’s research centre in Schenectady, NY is attempting to make flexible ceramics, a material that could be used in jet engine parts, allowing them to run at higher, more efficient temperatures. Scientists at the University of Texas have found a way of spinning carbon nanotubes into fibres to make the world’s toughest polymer.
Scientists are now probing and poking at things in even smaller dimensions. A group of researchers at Cornell University has invented a gadget that can detect particles at the attoscale, or a billionth of a billionth of a gram or metre. The device consists of a tiny cantilever that can detect masses as small as 6 attograms. By coating the cantilever with antibodies that bind to specific bacteria or viruses, the researchers hope to detect the presence of infections in humans, HIV for instance, at a much earlier stage than current tests, which require a build-up of the pathogen in the blood in order to detect.
All of which can make us forget that ultra-small-scale technology is still largely experimental. A recent survey of nanotechnology in the Economist proclaimed that while the potential is huge, “nano technology is (yet) neither an industry nor a market.”
In plastics, there have been a few modest nanotechnology success stories — the production of nano-filled plastic automotive body moldings going on the Chevrolet Impala, to name one. More successes will hinge on continued reductions in the cost of nanomaterials and production processes. If this is achieved, there is no doubt that the ability to make stuff with atomic scale precision will result in commercial materials with better properties, opening up new realms of innovation and business for manufacturers with the right know-how.