Thin films of silicon nanoparticles roll into flexible nanotubesJune 15, 2005CHAMPAIGN, Ill. - By depositing nanoparticles onto a charged surface, researchers at the University of Illinois at Urbana-Champaign have crafted nanotubes from silicon that are flexible and nearly as soft as rubber. "Resembling miniature scrolls, the nanotubes could prove useful as catalysts, guided laser cavities and nanorobots," said Sahraoui Chaieb, a professor of mechanical and industrial engineering at Illinois and a researcher at the Beckman Institute for Advanced Science and Technology. To create their flexible nanotubes, Chaieb and his colleagues - physics professor Munir Nayfeh and graduate research assistant Adam Smith - start with a colloidal suspension of silicon nanoparticles (each particle is about 1 nanometer in diameter) in alcohol. By applying an electric field, the researchers drive the nanoparticles to the surface of a positively charged substrate, where they form a thin film. Upon drying, the film spontaneously detaches from the substrate and rolls into a nanotube. Nanotubes with diameters ranging from 2 to 5 microns and up to 100 microns long have been achieved. Using an atomic force microscope, the researchers found that the Young's modulus (a measure of a material's elasticity) of the film was about 5,000 times smaller than that of bulk silicon, but just 30 times larger than that of rubber. "We suspect that the nanotubes consist of silicon nanoparticles held together by oxygen atoms to form a three-dimensional network," Chaieb said. "The nanotubes are soft and flexible because of the presence of the oxygen atoms. This simple bottom-up approach will give other researchers ideas how to build inexpensive active structures for lab-on-chip applications." "Because the silicon nanoparticles - which are made using a basic electrochemical procedure - have properties such as photoluminescence, photostability and stimulated emission, the resulting nanotubes might serve as nanodiodes and flexible lasers that could be controlled with an electric field," Nayfeh said. University of Illinois at Urbana-Champaign |
|||||||||||||||||||||
| Related Nanotubes Current Events and Nanotubes News Articles New study confirms exotic electric properties of graphene First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: a remarkably flat molecule made of carbon atoms arranged in hexagonal rings much like molecular chicken wire. Caltech scientists develop DNA origami nanoscale breadboards for carbon nanotube circuits In work that someday may lead to the development of novel types of nanoscale electronic devices, an interdisciplinary team of researchers at the California Institute of Technology (Caltech) has combined DNA's talent for self-assembly with the remarkable electronic properties of carbon nanotubes, thereby suggesting a solution to the long-standing problem of organizing carbon nanotubes into nanoscale electronic circuits. Breakthrough in industrial-scale nanotube processing Rice University scientists today unveiled a method for the industrial-scale processing of pure carbon-nanotube fibers that could lead to revolutionary advances in materials science, power distribution and nanoelectronics. Next-generation microcapsules deliver 'chemicals on demand' Scientists in California are reporting development of a new generation of the microcapsules used in carbon-free copy paper, in which capsules burst and release ink with pressure from a pen. Transforming Nanowires Into Nano-Tools Using Cation Exchange Reactions A team of engineers from the University of Pennsylvania has transformed simple nanowires into reconfigurable materials and circuits, demonstrating a novel, self-assembling method for chemically creating nanoscale structures that are not possible to grow or obtain otherwise. Study shows how carbon nanotubes can affect lining of the lungs Carbon nanotubes are being considered for use in everything from sports equipment to medical applications, but a great deal remains unknown about whether these materials cause respiratory or other health problems. Advance in 'nano-agriculture': Tiny stuff has huge effect on plant growth With potential adverse health and environmental effects often in the news about nanotechnology, scientists in Arkansas are reporting that carbon nanotubes (CNTs) could have beneficial effects in agriculture. A step toward better brain implants using conducting polymer nanotubes Brain implants that can more clearly record signals from surrounding neurons in rats have been created at the University of Michigan. The findings could eventually lead to more effective treatment of neurological disorders such as Parkinson's disease and paralysis. A recipe for controlling carbon nanotubes Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy‐saving transistors and wires. Friction force differences could offer a new means for sorting and assembling nanotubes Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved - among them, how to position and manipulate the tiny tubes. More Nanotubes Current Events and Nanotubes News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||