The Amazing World of Nanotechnology
The body of information surrounding nanotechnology is incredible. If you search the subject on Google, you will find well over a million entries. Interest in the field is unquestionable, and the buzz about its possibilities and potential increases daily, fueled by media hype and science fiction such as Michael Crichton's novel Prey.
The body of information surrounding nanotechnology is incredible. If you search the subject on Google, you will find well over a million entries. Interest in the field is unquestionable, and the buzz about its possibilities and potential increases daily, fueled by media hype and science fiction such as Michael Crichton's novel Prey . But just what is nanotechnology? More importantly, what might it mean to automation and controls?
Nanotechnology is not new. A piece of art in the British Museum called the Lycurgus Cup, a Roman glass cage cup, dates to the fourth century. The cup changes color as it reflects light because it contains nano-particles of gold and silver (each crystal is about 70 nm). Did the Romans know they were using nanotechnology? Probably not, but the fact remains that nano-materials have been impacting the world for centuries.
' 'Nano' has existed since the beginning of matter,' says Asish Ghosh, vice president, manufacturing advisory service, ARC Advisory Group. 'It is the development of the technology that is new—a new understanding, a new visualization made possible by advancing technology. What drove nanotechnology to the fore, I believe, was the development of IBM's scanning, tunneling microscope about 10 years ago.
'Using that device, researchers moved silicon atoms around to form the letters 'IBM', photographed it, and showed it to the world saying, ' this is nanotechnology: manipulating individual atoms.' This development and subsequent publicity led to an awakening in the ability to make things happen at the nanoscale,' Ghosh says.
More than small
Nanotechnology is typically defined as anything under 100 nm. Nano —from the Greek word for midget—means 10-9, or a billionth of a meter. An angstrom is 1/10thof a nanometer. Atoms are generally 2 to 10 nanometers. The diameter of a human hair is about 200,000 nm.
'A lot of people confuse nanotechnology with miniaturization,' says Ghosh. 'It is not the same. Nano does not merely mean smaller. It is putting atoms and molecules together in an ordered fashion to do something. Nanotechnology is the art and science of manipulating matter at the atomic or molecular scale.'
Manipulating molecules gives them different properties. As a result, they behave or perform differently. For example, says Ghosh, 'if you align carbon atoms in a certain order, they are much stronger than regular ones. With them, you can make a golf club that is much stronger and/or lighter than a traditional one.'
Rockwell Automation defines the term similarly. Dr. Sujeet Chand, senior vice president, advanced technology and chief technical officer, and Dr. Ram Pai, director of advanced technology labs, define nanotechnology as the manipulation, precision placement, measurement, modeling, and creation of sub-hundred nanoscale matter. However, 'I would modify that definition,' says Pai, 'to add 'in at least one dimension.' The question is: in which dimension? Carbon nanotubes, for example, can be very long or very narrow. The characteristic is important and must be considered.
'When you go down to nanoscale,' adds Pai, 'the surface area-to-volume ratio increases tremendously. Physical laws that govern behavior of matter at the nano scale are therefore distinctly different from those at the micro or macro scale.'
From lab to fab
Nanotechnology is an embryonic field. It is not yet widely commercialized, but progress is being made and applications already can be found from lab to fab. Roger Grace, president of high-technology consulting firm Roger Grace Associates, calls nanotechnology 'a new frontier.'
'We are in a discovery and development process with nanotechnology,' says Grace. 'Most of the nano-products we see today involve carbon nanotubes. They are the building blocks of many nano-products being sold today.'
Rockwell's Chand and Pai see the nano concept as evolving rapidly in three parallel phases:
Nano-materials and coatings. 'We see the use of nano-materials right now mostly on the commercial side,' says Chand, 'in products such as tennis balls, golf clubs, and clothing. On the industrial side, we're seeing their use in running boards on SUVs to give them more strength.' Nano-coatings are also found in a variety of manufacturing applications, such as coating electrical enclosures to absorb electromechanical radiation.
Nano-sensors. Nano-sensors have a lot of potential in industrial automation. Benefits include greater accuracy and more precision. They are expected to be able to detect drugs, hazardous materials, hazardous gases, and the like in minute quantities. Companies are working on sensors that detect cancers and those that react to hazardous particles in the air before any danger is presented to humans. A number of nano-devices are already on the market. (See 'Sensors Expo 2006: Nanotechnology sensor among products on display' Control Engineering Online News, www.controleng.com/article/CA6337950.html .)
Nano-electronics. Nanotechnology reportedly has the potential to double processor speeds. 'Going to the nanoscale,' says Chand, 'will give us not just a smaller package, but higher performance. It will help us embed electronics at a much lower level.'
Tools that manipulate at the nanoscale and below are developing simultaneously. These devices let engineers and scientists see the structure, alignment, and interfaces that determine the properties that might be relevant to the creation of nano-products. FEI Co.'s electron microscopes, focused ion beam systems, and hybrid equipment are among tools that help researchers and producers of nanotechnology and nanotechnology-enabled products see and manipulate at the nanoscale.
Matt Harris, vice president of worldwide marketing, FEI Co., elaborates with some examples. 'The semiconductor industry has been using nanotech tools for years for real-time process control and process diagnostics. It lets them do core research and then develop that research into a full-fledged process technology. Transmission electron microscopes enable core research on materials, material properties, and structures to help determine appropriate materials, coatings, and layering of materials for its processes. Do they have the right crystalline structure for a particular type of silicon? Is the silicon-oxide layer thick enough given a certain process?
'Nano-based inline equipment in production lines performs quality control. Wafers run through a system that measures the thickness of a particular layer. If it is within tolerance, the wafer passes. If not, it is fed back upstream where production parameters and the product are brought back into line.'
Potential applications also exist in the pharmaceutical and chemical industries. Nano-particles, says Harris, are being investigated for more effective drug delivery, and used to develop processes for creating a product and QC mechanisms to ensure the product is within tolerance for a given drug in a given application. In the chemical industry, he adds, researchers are looking for and at particles that can catalyze reactions more efficiently and make processes more efficient.
A long, winding road
Despite these positives, a number of factors are hindering the proliferation of nanotechnology. Lack of standards, according to FEI's Harris, is a major one. 'In the absence of standards, industry finds it difficult to do trade, to perform effective QC methodology, or to do good risk assessment,' he says. Nano-particles are already in fuel additives, paints, cosmetics, tires, golf balls, baseball bats, and more. Are there risks associated with nanotechnology products?'
Of course there are. Says ARC's Ghosh, 'Suppose you make a nano-silver or a nano-carbon with properties totally different from common traditional carbon or silver. What will it do to someone's skin? What happens if someone ingests it? We don't know how it will affect them. Work on standards is underway, but it's still a rather amorphous topic right now,' he adds.
Rahul Nayar, Technical Insights analyst, Frost & Sullivan agrees standards are required. 'No one really knows what nano-particles might do,' he points out. 'Carbon nanotubes have been shown, under certain conditions, to cause lesions in the lungs of rats. In other cases, toxicity has been found.' This industry needs some regulation, he says, but at the same time cautions that too many regulations could choke off progress. 'A balance between safeguards and advancement needs to be maintained,' he warns.
Industry and government, says FEI's Harris, need to collaborate to make these determinations. He sees de facto standards arising in the meantime. 'Carbon nanotubes, one of the earliest applications of nanotechnology, are being deployed in all kinds of production applications, from semiconductors to paints and coatings. Producers of carbon nanotubes will set the standards for these products,' he says, as formal standards are developed.
Another roadblock to the progress of nanotechnology is the unavailability of tools for low-cost, high-volume replication. 'We need investment and effort in nano-manufacturing techniques that create reproducible, low-cost components for making devices or products,' observes Roger Grace. 'We need ways to connect the nano-world to the micro-world to the macro-world so that something usable and practical can be delivered.'
In other words, nanotechnology needs to be commercialized. Nanotechnology admittedly has a lot of sex appeal, says Grace, but it must be practical. 'The real challenge is in the manufacturing. To create viable, cost-effective solutions, we need to be able to manipulate nano-particles and nano-materials for high-throughput manufacturing. If solutions are too expensive and/or too difficult to connect to the outside world, they will not be achievable.'
What might a nanotechnology future look like? FEI's Harris answers by pointing to recent market data. 'A key requirement for sustained growth of a particular technology,' he says, 'is the growth of private investment. Public investment can get something started, but it's private growth that keeps it going. Private investment has now surpassed public investment in nanotechnology, and that trend is expected to continue. That is an indicator of its long-term viability.'
Rockwell's Pai and Chand add numbers to those statements. Present figures, they say, show that some $5 billion a year is poured into global nano-research. That level is expected to hit $6 billion in 2006.
Frost & Sullivan's Nayar says nanotech is so fundamental that no industry will be untouched by it. 'Its main benefits will be an impressive increase in performance, and an impressive reduction in costs. In the near term, nanotechnology will improve existing applications, but in the future, it will lead to new products and developments.'
Nanotechnology, says Harris, can make things 10% lighter, or 5% more efficient, or 15% brighter. And when you make things cheaper, lighter, and more reliable, adds Roger Grace, 'everybody wins.'
Nano-resources: A few among many
The number and range of online resources related to nanotechnology topics are virtually infinite. Here are 15 of interest.
Practical nano: Energy harvests
A specialized lubricant formulated with nano-scale particles reduces the friction between a magnet and a non-magnet surface to a negligible level, 50 times lower than the friction between two Teflon surfaces. The technology, developed by Rockwell Scientific Co. (RSC) Nanotechnology R&D, is being used to harvest electric energy from random motion such as human movement, ocean waves, and many other sources.
Electrical energy is generated using Faraday's principle, the same as found in a 'shake-to-charge' flashlight. Shaking the flashlight causes a magnet to move across a coil, which generates an electric current that charges a capacitor. The nanotech development enables the magnet to move on a virtually frictionless surface, allowing the magnet to bounce back and forth across the coil many more times and generate more electricity as a result of the shake energy.
RSC has adapted the technology to produce a power charger for handheld devices. Under a program from the U.S. Defense Department's Defense Advanced Research Projects Agency (DARPA), RSC is currently developing a wave-energy harvesting device (shown) that will be installed onto ocean data-monitoring buoys to replace battery packs that have a finite lifetime.
Practical nano: Semiconductors, microdisplays
New-generation GAIN-HBT (GaAsInN HBT) wafers from Kopin Corp. are a nanotechnology-based product in volume production for the manufacture of tens of millions of cellular phone power amplifiers. The transistors improve power amplifier performance across key parameters to reduce operating voltage, increase RF performance, and improve temperature stability.
The product features a nano-engineered base layer that allows power amplifiers to maintain performance over greater temperature ranges and potentially achieve higher power efficiency. Band-gap engineering of the transistor base layer incorporates gradually varying amounts of indium (In) and nitrogen (N) in addition to gallium (Ga) and arsenic (As). Addition of the indium and nitrogen reduces the band-gap energy for low voltage operation, and the gradually varying composition creates an internal electric field for higher speed. Improved performance is achieved through precise control of the composition of the four elements within the 50-nm-thick layer.
Practical nano: Carbon nanotube-based epoxies
Carbon nanotubes (CNTs), sometimes called buckytubes, are cylindrical carbon molecules with properties that make them potentially useful in a variety of nanotechnology materials and applications. Properties include extraordinary strength and electrical characteristics that make them efficient heat conductors. They are among the most common nanotechnology materials used today.
Among CNT-based products are Zyvex Corp.'s line of epoxy concentrates, which blend several industry-standard epoxies with multi-wall or single-wall nanotubes, or carbon nanofibers, to deliver increased electrical and thermal conductivity and improved mechanical strength.
Zyvex's patented Kentera technology (a non-covalent modification of carbon nanomaterials) exfoliates, disperses, and adheres to the host material when it is combined with nanomaterials to incorporate the improved properties into the host polymer. Composite manufacturers may choose from a range of formulation options (the amount of CNTs in the product) to meet material design and price parameters. This field-emission-surface SEM (scanning electron microscope) image shows a polyurethane thin film composite loaded at 2.5 wt% with Kentera technology. The CNTs appear as white fibers retained in the matrix.
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