Vol.
29 No. 6
November-December 2007
Nanotechnology
- The New Chemistry
In
an earlier article (Jan-Feb
2006 CI,
p. 8), the author asked “Does Nanotechnology Have
a Sporting Chance?” and reviewed briefly the hype
surrounding the field. In a later article (Nov-Dec
2006 CI,
p. 10), he illustrated how lessons from Mother Nature
are resulting in the design of new nanotechnology applications.
In this third piece, Smith reviews how the subject of nanotechnology
has penetrated each divisions/discipline represented in IUPAC.
by Alan Smith
|
Dendrimer complex docking on cellular folate receptors. Source: Michigan Center for Biologic Nanotechnology. |
Although nanotechnology is not something new, the term itself is a relatively recent way of describing work at the atomic or molecular level. If you look back at the Nobel laureates in chemistry or physics, many of the recipients could be described as nanotechnologists. Physicist Richard Feynman, who received the Nobel Prize for Physics in 1965, is regarded as the father of nanotechnology since he had the vision to realize that changes in properties would be found at the nano-scale. However, it was not until 21 years later, in 1986, that two other Nobel laureates in physics, Heinrich Rohrer and Gerd Binnig, used scanning tunnelling microscopy to observe objects on the nano-scale.
Another 21 years on, and we wonder how we managed without the term nanotechnology. In the interim, some chemists have received the Nobel Prize for their nano-scale work, the most notable being Rick Smalley, Harry Kroto, and Robert Curl for their work on
fullerenes.
We hear so much about the flagging popularity of chemistry, but it is encouraging to see that nanotechnology is spicing things up for the chemist. There is not one division or standing committee in IUPAC that is unaffected by the advances in nanotechnology. In this feature, I would like to review how nanotechnology relates to the many disciplines represented in IUPAC.
Physical
and Biophysical Chemistry (Division I)
Physical chemistry is an essential part of understanding the
interactions that go into achieving novel properties that
are now being found at the nano-scale. Practical applications
range from modelling to produce nanoparticles of a consistent
size to examination of interactions at interfaces that provide
improved biocompatibility for tissue engineering.
Inorganic
Chemistry (Division II)
Nanoparticulate titanium dioxide is being used in a diverse
range of products, from sunscreens that offer protection from
cancer causing ultraviolet (UV) radiation to nano-coatings
on windows where the titanium dioxide actually uses UV light
to break down dirt in self-cleaning windows. There also are
air purifiers on the market that use similar catalytic processes,
such as NanoBreeze.
Other examples include the cerium oxide nanoparticles used in diesel fuel, which make it more efficient for engines, provide better mileage, and reduce emissions from exhaust pipes.
Precious metals offer another interesting area of nanotechnologoy in chemistry. Scientists have found, for example, that gold nanoparticles offer significantly improved catalytic properties. And nanoparticulate silver, which provides anti-microbial properties, is being used in a variety of products, such as wound dressings, baby milk cartons to prevent cross-contamination, food storage containers, and in the plastic parts of refrigerators to prevent mold formation. If Napoleon only knew that he lost his campaign in Russia because (although he had silver cutlery) his troops were using wooden spoons that supported microbial growth!
Organic
and Biomolecular Chemistry (Division III)
Organic chemistry is having a large influence on the pace
of nanotechnology development. For example, improved composites
are not achievable if the nano-ingredient is not dispersed
well in the polymer, so selection of the right “compatibilizer”
is essential. There also is a great deal of work going on
related to functionalizing carbon nanotubes for sensors.
A roadmap for the application of dendrimers into new materials—another discovery produced by nanotechnology—has been produced by scientists in Europe, and it describes their use in new inks, paints, and composites. Medical applications are at an early stage for these organics, but they offer great potential since dendrimers represent engineering at a biological-size scale. They show excellent potential as carriers for imaging contrast agents for enhanced organ, vascular, or tumor imaging, and for diagnostics.
Polymer
(Division IV)
Nanocomposites are already finding extensive applications,
where modified clays, carbon nanotubes, and particulates are
providing barrier properties, lighter weight and stronger
polymers, and functionalized surface applications. In order
to save energy, most car manufacturers are using clay composites
to replace heavy metal parts in cars. Even the fuel lines
in new cars are going plastic through the incorporation of
carbon nanotubes into the polymers to dissipate a charge.
However, it is with carbon nanotubes that we will see real
weight reductions because they may offer components that are
50 to 100 times stronger than steel, at one sixth the weight.
The implication of this for the aviation industry is revolutionary.
It is interesting to note, too, that car tires have been using carbon black nanoparticles for about a century now. This is the largest use of nanoparticles worldwide, at 6 million tonne per annum. Clay-based nanocomposites also provide barrier properties, and are being used in food packaging applications to give longer shelf life by eliminating oxygen and UV. Functional films are just thin nanocomposite layers, which offer surfaces that are anticorrosive, antiglare, antimicrobial, antiscratch, and heat resistant.
The Polymer Division’s project in nanoscience is aimed at proposing a list of terms and definitions for aggregation and self-assembly in polymers.
Analytical
Chemistry (Division V)
There is considerable analytical activity in nanotechnology,
especially with developments in atomic force microscopy. Viewing
nanoparticles, for example, is essential, since novel properties
are only achieved at the nano-scale. In addition, there is
a need to develop equipment to assess the extent and variety
of new properties that are achievable with nanotechnology.
Although there is currently emphasis on particle size and
distribution, it is becoming clear that surface area is a
crucial factor.
Chemistry
and the Environment (Division VI)
In 2002, Michael Crichton (author of Jurassic Park
and other science fiction books) published Prey,
a story that depicted clouds of nanorobots turning every living
thing into grey goo before the hero manages to stop them.
Unfortunately, many people thought that this type of catastrophe
was possible, and nanoparticles became the focus of environmental
and health groups and non-governmental organizations. The
resulting publicity led some groups to demand a complete moratorium
on manufactured nanoparticles, while others suggested that
the best policy is to proceed with caution.
The essential point is that the majority of what is described as nanotechnology has been around since creation. However, for certain nanoparticulates we need to carry out the usual tests and risk assessments that would be carried out with any new substance. Free nanoparticles, as opposed to those locked into a composite, for example, are more likely to be a problem, and manufacturers are most likely to be affected. In the same way, major companies are not going to take risks by putting untested material into their products.
Many developments in nanotechnology are viewed as having a beneficial effect on the environment. Pesticide companies are looking at nanotechnology to ensure that their products reach the intended targets, eliminating waste and soil contamination. Longer-lasting surfaces, improved by particular nano-coatings, should extend the life of many products and processes.
IUPAC chemists are involved with these issues as well; at the recent IUPAC Congress in Torino, Italy, scientists described how nanoparticulate titanium dioxide is incorporated into cement for buildings thereby helping to break down environmental pollution in the atmosphere.
Chemistry
and Human Health (Division VII)
Some of the most significant developments in nanotechnology
will come in the field of healthcare. Work on new diagnostics
indicate that increased sensitivity at the nano-scale will
enable problems to be detected before they have affected the
body, thereby reducing patient suffering and the length of
hospital stays. Developments in nanotechnology also are benefiting
tissue engineering, with new materials and surfaces that are
more biocompatible. Nanotechnology also is providing benefits
to the field of drug delivery.
Nanotechnology is being focused on some of the most significant healthcare problems, including cardiovascular diseases, cancer, musculoskeletal and inflammatory conditions, neurodegenerative and psychiatric diseases, diabetes, and infectious diseases. In the USA, significant funding is going to nanotechnology and cancer therapy, some of which is directed toward investigating better targeting of problematic cells.
Division VII has a project that could be described as nanotechnology entitled Prototype Analysis of Molecular Biomarkers in Cancer.
Chemical
Nomenclature and Structure Representation
(Division VIII)
This division has undertaken the complex task of nomenclature for rotaxanes and for fullerenes.
Committee
on Chemistry Education (CCE)
CCE has nanotechnology on their agenda. It is estimated that
there are now over 500 products on the market that are based
on nanotechnology. These are interesting and varied products,
so it is easy for both children and the general public to
grasp the significance of nanotechnology.
CHEMical
Research Applied to World Needs - Chemrawn Committee
CHEMRAWN XIV: Towards Environmentally Benign Processes and
Products, described new catalytic routes to chemicals, but
more recent work on nano-scale catalysts suggests that there
is great potential here for new production routes. Chemrawn
XV: Chemistry for Water, discussed using nanotechnology membranes
to provide clean water.
Because there are concerns in some quarters about nanotechnology, reports about its beneficial effects are being issued, specifically as they relate to the developing world. These effects have the potential to be a future CHEMRAWN conference topic.
Committee
on Chemistry and Industry (COCI)
Some people have suggested that nanotechnology is the next
industrial revolution, and there is not one industry sector
that is currently unaffected by nanotechnology.
Although
it is not possible to mention all the exciting nanotechnology
developments in this space—we are only seeing the “tip
of the iceberg”—it is likely that many more Nobel
Prize winners will be nano-
technologists.
Alan Smith <[email protected]> is an associate director of the UK government’s Micro Nano Technology Network, which is coordinating activities in nanotechnology throughout the UK. He is a member of the IUPAC Bureau and a member of the Committee on Chemistry and Industry.
Page
last modified 28 November 2007.
Copyright © 2003-2007 International Union of Pure and Applied Chemistry.
Questions regarding the website, please contact [email protected]
|