August 18, 2008
The Minutiae of Materials
By MEREDITH PRICE LEVITT
Nanotechnology takes the concept of small to new heights. Derived from the Greek word nanos, which means dwarf, nanotechnology deals with structures that are approximately one- billionth of a meter in size. That's about 1,000 times smaller than the diameter of one human hair.The applications for this technology are far-reaching - including aerospace, automotive, biomedical, microelectronics, semiconductors, pharmaceuticals, photo catalysts and sports equipment.
For ApNanoMaterials, a privately owned company founded in 2002 by Dr. Menachem Genut, president and CEO, and Aharon Feuerstein, chairman and CFO, its uses include reducing energy consumption by making more effective lubricants, increasing the effectiveness of solar absorption for improved energy conversion, and creating stronger, more durable bulletproof vests and bike helmets.
According to Dr. Niles Fleischer, vice president of business and product development at ApNano Materials in Rehovot, the story begins with geometric shapes that look similar to a soccer ball made up of pentagons and hexagons called fullerenes.
This soccer-ball-like shape of one of carbon's forms, discovered in 1985 by chemists Richard Smalley, Robert Curl and Harold Kroto, was one of the greatest breakthroughs in modern science and forms the basis of contemporary nanotechnology.
Yet, although these three scientists were the first to find this unusual carbon structure, its shape in human applications actually dates to more than 23 centuries ago, when the Greek geometer Archimedes discussed the truncated polyhedra in a now-lost work. In 1509, Leonardo da Vinci sketched the first open cage polyhedra in Luca Paciolio's treatise De Divina Proportione.
The C60 carbon molecule discovered in the 1980s called buckminsterfullerene (bucky balls) is named in honor of Buckminster Fuller, a well-known architect. Fuller's 76- meter diameter geodesic dome wowed the world at Montreal's Expo in 1967. It was one of the strongest structures ever built, but also incredibly lightweight and flexible.
Examining how the dome was constructed with triangles and hexagons helped chemists Smalley, Curl and Kroto understand how C60 carbon - a closed cage molecule made up of 60 atoms and shaped like a soccer ball - is formed.
In 1992, Prof. Reshef Tenne of the Weizmann Institute, along with Genut, Dr. Lev Margulis and Prof. Garry Hodes, discovered non- carbon-based structures known as inorganic fullerenes. Until that time, it was thought that fullerenes could only be formed with carbon, and their discovery led to an exciting innovation. They realized that certain inorganic compounds that normally occur as large, flat platelets could be synthesized into smaller nanospheres and tubes.
Under the right conditions, these onion-shaped molecules form multi-walled tubes that are incredibly strong, yet incredibly small. "Kroto tested these inorganic fullerenes and found that they could withstand greater impacts than their carbon counterparts, and this led to the idea of using them for bulletproof vests, bike helmets and armored vehicles," says Fleischer.
After obtaining an exclusive license from the Yeda Research and Development Company (the commercial arm of the Weizmann Institute) to manufacture, commercialize and sell this new class of nanomaterials based on inorganic compounds, Genut and his team started to investigate the applications.
"We realized that by adding these inorganic fullerenes to lubricants, like oil and grease, we could increase the efficiency and thereby lessen the resistance and save energy," says Fleischer.
These inorganic fullerenes are added to the lubricants to reduce friction, which not only reduces the energy spent by engines but increases the life of the engine by lessening the overall wear and tear. The additives, trademarked under the name NanoLub, are sold all over the world and in Sonol gas stations across Israel. You simply buy some NanoLub and mix in with the oil already in your car's engine.
The nanospheres also have solar energy applications. "ApNano Materials' nanoparticles are excellent optical absorbing materials and among the best substances absorbing light in the visible and near infrared wavelengths," Genut recently said in an article in Nanotechnology Now's on-line magazine.
Capable of absorbing 98 percent of the sun's radiation, they form incredibly effective coatings for solar panels, satellites, cameras and lens barrels that can be used to create energy. "I like to tell people that they can have the nanospheres in any color they want as long as it's black," says Fleischer with a chuckle.
When it comes to nanotechnology, the old adage that bigger is better couldn't be more wrong. It seems like good things really do come in small packages.
Originally published by MEREDITH PRICE LEVITT.
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