Add nanotubes and stir - with the right forceJuly 24, 2006Polymer scientists at the National Institute of Standards and Technology have some stirring results to share with researchers and companies developing new, advanced composite materials with carbon nanotubes-mix carefully. In a paper for Physical Review Letters,* they explain how the amount of force applied while mixing carbon nanotube suspensions influences the way the tiny cylinders ultimately disperse and orient themselves. In turn, the final arrangement of the nanotubes largely dictates the properties of the resultant materials. Measuring only a few nanometers in diameter (the width of a handful of atoms), carbon nanotubes possess many superior properties that make them highly desirable additives in composites, a class of engineered materials made by blending polymers and fibers or by combining other types of unlike materials. Mixed in polymeric materials, carbon nanotubes can provide incredible strength, toughness and electrical conductivity. The trouble is, nanotubes stick to each other and form networks that tend to stay fixed in place. Apply enough force, the networks will flow but usually end up in tangled clumps. The resultant nanocomposites are difficult to mold or shape, and their properties fall short of expectations.
In an elegantly simple result, NIST researchers Erik Hobbie and Dan Fry found that networks of carbon nanotubes respond predictably to externally applied force. The networks also showed behavior reminiscent of more conventional materials that align spontaneously under the forces of Brownian motion-the random motion of particles in a fluid famously described mathematically by Einstein. The response was so predictable that the scientists mapped out the relationship in the form of a phase diagram, the materials science equivalent of a recipe. Using their "phase diagram of sticky nanotube suspensions," other researchers can estimate the order that will result when applying a certain amount of force when mixing a polymer fluid with a particular concentration of nanotubes. The recipe can be used to prevent entanglement and to help achieve the nanotube arrangement and orientation associated with a desired set of properties. National Institute of Standards and Technology (NIST) Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Amphibian Stem cells Bladder Cancer Ice Core Enzyme Tonsillectomy Cholesterol Bacteria Sudden Infant Death Syndrome Climate Warming Natural Selection Black Holes Puberty Arthritis Tomato Flu Virus Overweight Genomes Language Nanomaterials Chronic Infection Coronary Artery Disease Protons Aurora Influenza Virus
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Related Nanotube Current Events and Nanotube News Articles Penn materials scientist finds plumber's wonderland on graphene Engineers from the University of Pennsylvania, Sandia National Laboratories and Rice University have demonstrated the formation of interconnected carbon nanostructures on graphene substrate in a simple assembly process that involves heating few-layer graphene sheets to sublimation using electric current that may eventually lead to a new paradigm for building integrated carbon-based devices. A Billion Year Ultra-Dense Memory Chip When it comes to data storage, density and durability have always moved in opposite directions - the greater the density the shorter the durability. A quicker, cheaper SARS virus detector -- one easily customizable for other targets Members of a USC-led research team say they've made a big improvement in a new breed of electronic detectors for viruses and other biological materials - one that may be a valuable addition to the battle against epidemics. Inexpensive plastic used in CDs could improve aircraft, computer electronics If one University of Houston professor has his way, the inexpensive plastic now used to manufacture CDs and DVDs will one day soon be put to use in improving the integrity of electronics in aircraft, computers and iPhones. UCLA researchers develop new method for producing transparent conductors Researchers at UCLA have developed a new method for producing a hybrid graphene-carbon nanotube, or G-CNT, for potential use as a transparent conductor in solar cells and consumer electronic devices. New nanotube coating enables novel laser power meter The U.S. military can now calibrate high-power laser systems, such as those intended to defuse unexploded mines, more quickly and easily thanks to a novel nanotube-coated power measurement device developed at the National Institute of Standards and Technology (NIST). UCLA physicists create world's smallest incandescent lamp In an effort to explore the boundary between thermodynamics and quantum mechanics - two fundamental yet seemingly incompatible theories of physics - a team from the UCLA Department of Physics and Astronomy has created the world's smallest incandescent lamp. Sandia researchers construct carbon nanotube device that can detect colors of the rainbow Researchers at Sandia National Laboratories have created the first carbon nanotube device that can detect the entire visible spectrum of light, a feat that could soon allow scientists to probe single molecule transformations, study how those molecules respond to light, observe how the molecules change shapes, and understand other fundamental interactions between molecules and nanotubes. Nanoneedle is small in size, but huge in applications Researchers at the University of Illinois have developed a membrane-penetrating nanoneedle for the targeted delivery of one or more molecules into the cytoplasm or the nucleus of living cells. Nanoribbons from sliced open nanotubes: new, faster, more accurate method from Stanford A world of potential may lie tied up in graphene nanoribbons, particularly for electronics applications. But researchers have been hampered in their efforts to fully explore that potential because they had no reliable way of creating the large quantities of uniform nanoribbons needed to conduct extensive studies. More Nanotube Current Events and Nanotube News Articles |
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