The paper was written by Strus materials engineering doctoral student Luis Zalamea Raman Byron Pipes, the John Leighton Bray Distinguished Professor of Engineering NASA engineer Cattien Nguyen and Eric Stach, an associate professor of materials engineering. Mechanical engineering doctoral student Mark Strus made the first peeling-force measurements for nanotubes in research based at the Birck Nanotechnology Center in Purdue's Discovery Park.įindings were detailed in a research paper published in February in the journal Nano Letters. "These forces are very relevant on this size scale because a nanometer is about 10 atoms wide." "Operating in a nanoscale environment is sort of like having flypaper everywhere because of the attraction of van der Waals forces," Raman said. Researchers are trying to learn about the physics behind the "stiction," or how the tiny structures stick to other materials, to manufacture everything from nanoelectronics to composite materials, "nanotweezers" to medical devices using nanotubes, nanowires and biopolymers such as DNA and proteins, he said.įlexible carbon nanotubes stick to surfaces differently than larger structures because of attractive forces between individual atoms called van der Waals forces. Knowing how much force is needed to pull a material off of another material is essential for manufacturing, but no tests exist for nanoscale structures, said Arvind Raman, an associate professor of mechanical engineering at Purdue. Yes, some regulations may need to be reinterpreted, but the current regulatory framework is sufficient to cover these materials once that reinterpretation occurs.So-called "peel tests" are used extensively in manufacturing. "There are already regulations covering hazardous materials the question is when you start categorizing a new material as hazardous, and that's not really a regulation issue. Peterson said there are serious questions over how applicable that study really is.Īs for regulation, it already exists, said Kevin Ausman of the Center for Biological and Environmental Nanotechnology. "Only a handful of toxicological studies exist on engineered nanoparticles, but not-so-tiny red flags are popping up everywhere," said the ETC's Thomas, alluding to recent reports that nanoparticles caused brain damage in fish in just 48 hours. Howard, a toxicopathologist at the University of Liverpool, told Wired News in January. "The indications are that as particles get small, they become much more chemically reactive and, therefore, possibly much more toxic," Dr. But along with those benefits come risks, largely unknown ones. Nanotech promises many benefits - from better products to, potentially, new ways to cure disease. Nanoparticles of metal oxides, however, are transparent, but can still block out ultraviolet light. Metal oxides are opaque, and are used in white sun-block creams. The phenomenon is demonstrated in sun-blocking products. But new, engineered, nanoparticles have unique properties, which is why venture capitalists are willing to spend a fortune developing them. Nanoparticles in the air have existed since man discovered fire, and probably before. The issue is contentious not least because it's complex.
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