Posted by admin on May 30, 2010 in Articles | 0 comments
Buckypaper is 10 times lighter but potentially 500 times stronger than steel when sheets of it are stacked and pressed together to form a composite. Unlike conventional composite materials, though, it conducts electricity like copper or silicon and disperses heat like steel or brass.
Buckypaper is made from tube-shaped carbon molecules, 50,000 times thinner than a human hair, that were first developed in the early 1990s. Buckypaper owes its name to Buckminsterfullerene, or Carbon 60 – a type of carbon molecule whose powerful atomic bonds make it twice as hard as a diamond.
Among the possible uses for buckypaper that are being researched at FAC2T:
If exposed to an electric charge, buckypaper could be used to illuminate computer and television screens. It would be more energy-efficient, lighter, and would allow for a more uniform level of brightness than current cathode ray tube (CRT) and liquid crystal display (LCD) technology. As one of the most thermally conductive materials known, buckypaper lends itself to the development of heat sinks that would allow computers and other electronic equipment to disperse heat more efficiently than is currently possible. This, in turn, could lead to even greater advances in electronic miniaturization. Because it has an unusually high current-carrying capacity, a film made from buckypaper could be applied to the exteriors of airplanes. Lightning strikes then would flow around the plane and dissipate without causing damage. Films also could protect electronic circuits and devices within airplanes from electromagnetic interference, which can damage equipment and alter settings. Similarly, such films could allow military aircraft to shield their electromagnetic “signatures,” which can be detected via radar.
So far, buckypaper can be made at only a fraction of its potential strength, in small quantities and at a high price.
Carbon nanotubes are already beginning to be used to strengthen tennis rackets and bicycles, but in small amounts. The epoxy resins used in those applications are 1 to 5 percent carbon nanotubes, which are added in the form of a fine powder. Buckypaper, which is a thin film rather than a powder, has a much higher nanotube content – about 50 percent.
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Posted by admin on May 24, 2010 in Articles | 0 comments
With all of the technology that is being continuously introduced and used, it would only seem logical in our quest for a green world to apply some of the renewable energy efforts to this spectrum. That is exactly what some scientists are looking into with their research on how nanotechnology can be used with lithium batteries.
According to Science News, a report that will be published in International Journal of Nanomanufacturing asserts that “carbon nanotubes can prevent such batteries from losing their charge capacity over time.” The batteries they are speaking of are the lithium-based batteries that are found in commonly used devices such as MP3 players, laptop computers, and cell phones.
As any of us who partake of these various technologies are quite aware of, with continued use, the battery power just seems to lose its life. As the news story reports, elements such as hot and cold temperatures help this reduction process along even more. Scientists have been researching this degradation process for awhile, and have looked into silicon to replace the universally used lithium-ion batteries. However, due to the fast rate that silicon also degrades, they have had to search even further.
This is where nanotechnology comes into play. As Science News states, “Shengyang’s Hui-Ming Cheng and colleagues have turned to carbon nanotubes (CNTs) to help them use silicon (Si) as the battery anode but avoid the problem of large volume change during alloying and de-alloying.” By introducing the carbon nanotubes to the silicon, they seem to be solving some of the problems that previously existed.
The whole process is quite amazing. “The researchers grew carbon nanotubes on the surface of tiny particles of silicon using a technique known as chemical vapor deposition in which a carbon-containing vapor decomposes and then condenses on the surface of the silicon particles forming the nanoscopic tubes. They then coated these particles with carbon released from sugar at a high temperature in a vacuum. A separate batch of silicon particles produced using sugar but without the CNTs was also prepared.”
The scientists used these two diverse batches and compared them. What they found was remarkable – the batch using the carbon produced a discharge capacity twice that of the one which only contained the silicon particles.
There seems to be many reasons that have prompted research into better material used to create batteries. Reports of fires found to be ignited by lithium-ion batteries, although rare, seem to have caused much attention to be placed on safer materials. The general complaint many have regarding the increased reduction of device batteries after continued use is likely another reason that prompted the research. Whatever the likely combination was, this new research could be monumental in how users of technological devices power up their gadgets.
Nanotechnology is not the only material researchers are using in their quest for a better battery, but it does seem to be one of the options that show much promise.
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Posted by admin on May 18, 2010 in Articles | 0 comments
Like the California gold rush of 1849, the emergence of nanotechnology presents both an enormous opportunity and enormous risks. Just as new techniques, rewards, and challenges emerged during the gold rush era, nanotechnology exploration will inevitably lead to the development of new tools to achieve new breakthroughs, the opportunity for creating enormous wealth, and unfortunately, the potential for environmental, health, and safety disasters. Although nanotechnology undoubtedly will create disruptive technologies that will spin off many new jobs, it also has the potential for displacing existing workers unprepared to take on these new technologies.
The first fruits of nano R&D are already being harvested as disciplines as diverse as materials, electronics, biotechnology, and computing rush to exploit nanotechnology’s potential. Many consumers have already become familiar with nano-derived products, such as improved types of cosmetics, fabrics, paints, plastics, or personal electronics.
Nanotechnology offers all-but-unlimited opportunities for those who can develop the next exotic material or electronic component that is cheaper, better, and faster than today’s CMOS devices. It also holds huge promise for those who will create the tools needed to produce these materials and devices. Despite the recession, corporate and government labs around the world continue to invest billions in nanoscience research. Unfortunately, unless the public and private sectors work in cooperation to develop standardized test methods and guidelines, the transition from the laboratory to the marketplace could create many of the same problems as the California gold rush did, particularly for the environment. However, with careful planning, we can have the appropriate terminology, test measurement methods, reporting, and environmental, safety, and health safeguards in place early enough to ward off serious consequences.
Why Are Standards So Important?
Very simply, standards are crucial to achieving a high degree of interoperability, creating order in the marketplace, simplifying production requirements, managing the potential for adverse environmental impacts, and most important, ensuring the safety and health of those developing and using the next generation of materials and devices.
Standards for nano terminology, materials, devices, systems, and processes will help establish order in the marketplace. For R&D researchers and engineers, standards make it possible to make measurements and report data consistently in a way that others can understand clearly. Those responsible for developing standards will be at the forefront in understanding the need for, and creation of, new characterization tools, processes, components, and products to help jump-start this emerging field. This kind of approach can represent a competitive tool in global markets. Creating a standard in advance of the release of a new technology allows both manufacturers and consumers to gain greater confidence in it, promoting greater acceptance and faster adoption.
The following examples illustrate the importance of early standards development.
Carbon Nanotubes
Although some of the more sophisticated electronics and medical advances scientists have envisioned are still years down the road, the development of some nanoscale raw materials, particularly carbon nanotubes (CNTs), is already well underway. Years before CNTs were commercially available, industry observers heard how they would bring significant performance advantages to electronics, enhance materials to make them stronger and lighter, and might even be part of the solution to our energy problems. This industry buzz, plus the massive private and public sector investments in nano research, built interest at every level. In 2000, the late Dr. Richard Smalley spun off his work to form Carbon Nanotechnologies Inc. (now Unidym) with the goal of commercializing his method of producing large batches of high-quality nanotubes. Unfortunately, at that point, there were no manufacturing standards or guidelines for ensuring the reproducibility of the company’s manufacturing process. There were also no known test and measurement guidelines for verifying the reproducibility and proving results on a large scale. Given this, how would the company have assured its customers of the quality of its products? Or just as important, how could customers choose confidently among various manufacturers’ CNTs based on their product description?
Buying carbon nanotubes isn’t like buying baseballs or bananas—it’s impossible to judge their quality just by looking at them. En masse, CNTs basically look like a pile of soot. How can incoming inspectors verify what they have received? How do they know whether they are single-walled or multi-walled tubes? Given the different species of carbon nanotubes now available (tubes that are metal or semiconducting, based on their chirality), most companies looking to purchase nanotubes would have had no basis on which to ensure that what they received is what they ordered. However, with a standard in place, customers have the tools needed to verify the materials they are purchasing.
Materials Characterization Techniques
Characterizing the specific properties of raw CNTs or other nanoscale materials is obviously important, but what about nanoscale materials intended to enhance bulk materials or to create new materials with enhanced properties? What kinds of testing and reporting standards are needed? Must both mechanical and electrical testing be included when designing new materials?
Probing and microscopy are used routinely to uncover new materials properties, but probe force should also be considered. What happens to the electrical properties of a nanoscale material under a particular probe force? Some very thin materials can exhibit localized phase transformations at the probing location, which can change their electrical characteristics. What kind of testing standards and guidelines are necessary to support probe force?
Nanomechanical testing has become a popular way of determining quantitative, small volume mechanical properties. Conceptually, nanoindentation is a relatively straightforward technique in which an indenter probe of a well-known geometry is pushed into and withdrawn from the material’s surface while the force and displacement are continuously recorded. Conductive nanoindentation, a new technique, combines nanoindenter hardware with a conductive probe and voltage/current source-and-measure instrumentation to produce a time-based correlation of force, displacement, voltage, and current. When used in tandem, nanomechanical and electrical measurements have proven highly sensitive to probe/sample contact conditions, as well as to material deformation behavior, which adds important information to that obtainable from nanoscale point measurements.
From a standards perspective, the most important question becomes whether a broader audience would find this testing method acceptable. Would the nanomaterials community accept this as a best practice measurement method and as a potential standard test methodology?
This is the first of a two-part series about standards in nano technology.
Jonathan Tucker is the Senior Marketer for Scientific Research Instruments and Research and Education business at Keithley Instruments in Cleveland, Ohio. He joined the company in 1987 and has held numerous positions including Test Engineer, Applications Engineer, Applications Manager, and Product Marketer. His current focus is business strategy and product development of electrical characterization and measurement tools for nanotechnology applications.
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