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Few industries will not be affected by the influence of nanotechnology. It is about new ways of making things. It promises more for less: smaller, cheaper, lighter and faster devices with greater functionality, using less raw material and consuming less energy. Faster computers, biocompatible materials, surface coatings, catalysts, sensors, telecommunications, magnetic materials and devices, are just some examples of where nanotechnology has been embraced.
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Definition
Originating from the Greek word meaning “dwarf”, in science and technology the prefix “nano” signifies 10-9, i.e. one billionth (= 0.000000001). A nanometre is a billionth of a metre (10-9m), which is the length of ten hydrogen atoms.
Nanotechnology can be described as manipulating the attributes of matter at the nanoscale to create products with new functionalities at the macroscale. It can be defined in its simplest terms as ‘engineering at a very small scale’.
Nanotechnology is a particularly exciting area of technology as it encompasses a whole range of activities from the creation of tiny structures with nanoscale features, to the manipulation of single atoms and molecules in order to produce novel materials and devices in new ways, and with entirely new properties.
From Micro to Nano
Nanotechnology, in one sense, is the natural continuation of the miniaturization revolution that we have witnessed over the last decade, where millionth of a metre (10-6m) tolerances (microengineering) were commonplace. This has been apparent in the scaling down of mobile phones, computers, cameras and even satellites, to cite a few examples. These products, as well as others such as CDs and CD-players, sensors (such as accelerometers in car airbags) and inkjet printers contain components with nanometre features.
Nanotechnology is still at a very early stage. Its future impact on industrial processes is difficult to determine but progress is being made. For instance, nano carriers are used in medicine for delivering specific drugs to specific sites, new 'smart' coatings made up from nano size elements are beginning to be used for industrial applications, and Micro-Electro-Mechanical Systems (MEMS), which are built up from nano size elements, are finding applications.
Because of the opportunities nanotechnology opens up to create new features and functions, it is expected be a key factor in future global markets. New technologies are essential to economic success and may provide the solution to many medical, social and environmental problems. Early evaluation of nano-innovations and their future market potential is vital in order for industry to play an active role in shaping future markets.
However, for emerging technologies to be adopted into the mainstream, they will need to demonstrate performance advantages as well as total cost performance benefits. This transition is beginning to occur. Nanotechnology offers smaller, cheaper, lighter and faster devices with greater functionality, using less raw material and consuming less energy.
New applications
Advances in nanotechnology are already ushering in new applications that are leading to improved products across a broad realm of sectors, from textiles to electronics. Few industries will escape the influence of nanotechnology in the medium term. It is likely to make an impact by providing methods to overcome well-understood and long-predicted barriers that stand in the way of the improvement of existing technologies.
Nanotechnology is of global interest. It has attracted more public funding than any other single area of technology. It is the one area of R&D that is truly multidisciplinary. The contribution of nanotechnology will not be made in isolation from other rapidly developing areas of science. In particular, advances in biology and biotechnology, information technology and nanotechnology itself, are likely to reinforce each other in a synergistic way.
Nanotechnology related R&D is increasingly looking to processes from the living world to provide solutions in the 'non-living' world (materials, processes, products) and finding ‘disruptive’ solutions to technological problems.
A disruptive technology is one that completely replaces an existing technology, rather than merely taking it to a higher level. For example, when the printing press arrived, publishing was revolutionized, monks no longer had to labour to create books for a select few, they could be produced quickly, and consequently became widely available in a short time.
Many of the companies currently working with nanotechnology are applying knowledge of the nanoscale to existing techniques, whether it is improving drug delivery mechanisms for the pharmaceutical industry, or producing clay nanoparticles for the plastics industry. At present, nanotechnology is an enabling technology, but with the potential to be highly disruptive. Nanotechnology depends on applying a fundamental understanding of how nature works at the atomic scale. New industries will be generated as a result of this understanding, just as the understanding of how electrons can be moved in a conductor by applying a potential difference led to electric lighting, the telephone, computing, the internet and other industries.
Nanoscale products themselves, such as a gram of nanotubes, have zero intrinsic value. The real value of the nanotubes is in their application, whether within an existing industry, or enabling the creation of a new one. The market for nanoscale materials is currently small, possibly only currently £20 million worldwide. However, the market for the products in which they are used is much larger, possibly £30 billion plus. It is the potential for nanotechnology to be disruptive in these and other markets that is generating such intense competition and interest.
Nanotechnology already underpins innovative applications in industries as diverse as the IT, automotive, cosmetics, chemicals and packaging industries. It is the promise of radical new applications, amongst them energy storage, diagnostics, measurement and testing, analysis, and drug delivery, robotics and prosthetics, where nanotechnology will prove disruptive to existing products and markets.
Nano in medicine
In medicine, nanotechnology is enabling faster, cheaper and more efficient diagnostic techniques. Instead of sending a sample of blood away to a laboratory to be analysed, it is possible already to have a diagnosis within a few minutes using a hand-held monitor, not dissimilar to a mobile phone.
More sophisticated versions of this diagnostic technique, combined with powerful computers (which also benefit from components with nanoscale features) are used for speeding up the new drug discovery process, where many ‘target’ drugs can be quickly assessed and retained or discarded in a fraction of the time normally taken.
Nanotechnology is also useful in the battle against disease. The manufacturing of known drugs in nanoparticle form, often with special coatings, can be designed to target specific diseased tissue and activated only when they reach it. In another interesting development, it has been noted that many drugs are far more effective in nanoparticle form, and in much lower dosages.
To look at some fascinating examples of nanotechnology applications in other areas, it has been discovered that clay minerals in nanopowder form can be disseminated, for example, in polymers. Polymer coatings themselves are notoriously easily damaged, but the inclusion of only 2% of clay minerals as nanoparticles makes a dramatic difference, creating coatings that are tough, durable and scratch resistant. This has implications for new paints, ‘varnishes’ - even for space vehicles and aircraft - or for any situation where the underlying material fits the bill in terms of say lightness and ease of working, but needs to be protected from a demanding environment.
It is interesting to reflect on the fact that particles at the nanoscale are below the wavelength of visible light, and therefore cannot be seen. Consequently, they can impart new properties, while being invisible themselves! Fluorescent nanoparticles (called ‘quantum dots’) have a whole range of possible applications. They are invisible until ‘lit up’ by ultraviolet light and can be made to exhibit a range of colours, depending on their composition. This throws up opportunities for ‘tagging’ counterfeit articles, stolen goods, illicit drugs, and even in health applications, such as tracing the course of therapeutic drugs in the human body.
Nanomaterials
The term ‘nanomaterials’ encompasses a wide range of materials including nanocrystalline materials, nanocomposites, nanoparticles, carbon nanotubes and quantum dots. The common link between all these materials is that they all have microstructural features on the nanoscale.
Nanomaterials are typically particles measuring in the size range of 1 to 100 nanometres (nm). Nanoparticles serve as the “building blocks” for nanomaterials and devices. They include nanocrystalline materials such as ceramic, metal and metal oxide nanoparticles; fullerenes, nanotubes and related structures; nanofibres and wires and precise organic as well as hybrid organic-inorganic nanoarchitechtures, such as dendrimers and polyhedral silsesquioxanes, respectively. By virtue of their structure, nanomaterials exhibit different physical, chemical, electrical and magnetic properties from conventional materials, which can be exploited for a variety of structural and non-structural applications.
Nanoparticles
Nanoparticles offer various unusual properties that are not observed in the corresponding bulk crystals, and as a result have generated great interest in academia and industry. These particles have large surface areas and high surface reactivity and provide enormous flexibility for in situ applications. Nanoparticles can be made of a wide range of materials, the most common being ceramics, which are split into metal oxide ceramics (titanium, zinc, aluminium and iron oxides) and silicate nanoparticles (generally in the form of nanoclays). They are generally designed and manufactured with physical properties tailored to meet the needs of the specific application they are going to be used in.
Certain types of nanoparticles are available commercially in the form of dry powders or liquid dispersions. The latter is obtained by combining nanoparticles with an aqueous or organic liquid to form a suspension or paste. It may be necessary to use chemical additives (surfactants, dispersants) to obtain a uniform and stable dispersion of particles. With further processing steps, nanostructured powders and dispersions can be used to fabricate coatings, components or devices that may or may not retain the nanostructure of the particulate raw materials. Some current applications and developments include:
>> ICI - titanium dioxide for sunscreens - ~50nm;
>> BASF - Titanium dioxide for fibre treatment - ~ 500nm;
>> Oxonica – nanosized phosphors for electronic displays, catalysts, cosmetics and quantum dots;
>> QinetiQ – use of plasma processing technology for production of nanoparticles by the tonne;
>> Nanoco – manufacture of quantum dots. These materials could be of great value for security device applications including the printing of currency.
From both fundamental and applied perspectives, nanostructured materials and nanocomposites exhibit outstanding deformation behaviour. They offer higher performance, reliability and enhanced functionality. Nanometre-sized grains contain only about 900 atoms each. As the grain size decreases, there is a significant increase in the volume fraction of grain boundaries or interfaces. This characteristic strongly influences the chemical and physical properties of the material. For example, nanostructured ceramics are tougher and stronger than the coarser grained ceramics.
Nanophase metals exhibit significant increases in yield strength and elastic modulus. It has also been shown that other properties (electrical, optical, magnetic, etc.) are influenced by the fine-grained structure of these materials. Using a variety of synthesis methods, it is possible to produce nanostructured materials in the following forms: thin films, coatings, powders and as a bulk material. There is also considerable interest in the generation of carbon nanostructures. In addition, the use of nano-sized materials as fillers for composite materials is generating interest, specifically in the case of polymer nanocomposites.
Understanding surfaces and interfaces is a key challenge for those working on nanomaterials, and one where new imaging and analysis instruments are vital. Nanomaterials are not simply another step in the miniaturization of materials. They often require very different production approaches. Although many nanomaterials are currently at the laboratory stage of manufacture, a number of them are being commercialized.
"If you look at the genesis of lots of our technology - gas turbines, aircraft engines, stuff like that - we are the world's largest patent producer in material science and always have been. It's natural for us to begin work on nanotechnology because, in essence, that is going to be the next generation of materials science. So we spend a lot of money on that.”
Jeffrey Immelt, chairman and chief executive officer of General Electric Co |
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