New and exotic materials

A standard technique for producing two-dimensional crystals just one atomic layer thick has been developed by physicists in the UK and Russia. The crystals, which are essentially gigantic 2D molecules, were created by Andre Geim and co-workers at Manchester University and the Institute for Microelectronics Technology in Chernogolovka. The structures were made by simply rubbing the freshly cleaved surface of a layered crystal onto another surface, like drawing chalk on a blackboard. This micromechanical "peeling" created flakes, some of which were -- unexpectedly -- just one layer thick. The crystals are stable and could be used to make transistors and sensors (Proc. Natl. Acad. Sci. 2005 102 10451).

A standard technique for producing two-dimensional crystals just one atomic layer thick has been developed by physicists in the UK and Russia. The crystals, which are essentially gigantic 2D molecules, were created by Andre Geim and co-workers at Manchester University and the Institute for Microelectronics Technology in Chernogolovka. The structures were made by simply rubbing the freshly cleaved surface of a layered crystal onto another surface, like drawing chalk on a blackboard. This micromechanical "peeling" created flakes, some of which were -- unexpectedly -- just one layer thick. The crystals are stable and could be used to make transistors and sensors (Proc. Natl. Acad. Sci. 2005 102 10451).

Physicists in France have discovered a liquid that "freezes" when it is heated. Marie Plazanet and colleagues at the Université Joseph Fourier and the Institut Laue-Langevin, both in Grenoble, found that a simple solution composed of two organic compounds becomes a solid when it is heated to temperatures between 45 and 75°C, and becomes a liquid when cooled again. The team says that hydrogen bonds are responsible for this novel behaviour (M Plazanet et al. 2004 J. Chem. Phys 121 5031).

Scientists from IBM's Zürich Research Laboratory and Chalmers University of Technology in Sweden have found a way to alter a single atom.

The researchers used a low-temperature scanning tunneling microscope and a voltage pulse to place an electron on an individual gold atom, then remove the electron. Regular atoms are neutral, while ions -- atoms with more or fewer electrons -- carry a charge.

The gold atom, positioned on an ultrathin film of sodium chloride, remained stable during the operation, despite the change in charge. The gold atom was kept stable by small changes in the positions of nearby atoms in the film.

Terrible, horrible things can be done to this millimeters-thick patch of shimmering material crafted by chemists at NanoSonic in Blacksburg, Virginia. Twist it, stretch it double, fry it to 200°C, douse it with jet fuel—the stuff survives. After the torment, it snaps like rubber back to its original shape, all the while conducting electricity like solid metal. “Any other material would lose its conductivity,” says Jennifer Hoyt Lalli, NanoSonic’s director of nanocomposites.

The abused substance is called Metal Rubber, and, according to NanoSonic, its particular properties make it unique in the world of material chemistry. As a result, the company’s small office has been flooded with calls from Fortune 500 companies and government agencies eager to test Metal Rubber’s use in everything from artificial muscles to smart clothes to shape-shifting airplane wings.

Scientists have developed an invisible coating that will waterproof almost anything including mobile phones, it was revealed today.

The revolutionary nanometre-thick coating was first researched to protect soldiers’ suits against chemical and biological warfare agents by Defence Science and Technology Laboratory (Dstl) at Porton Down and the University of Durham.

The new invention, which is three times more water repellent than Teflon, could radically change sportswear, clothing, mobile phones and medical devices. Apart from its military uses Dstl is now trying to capture the civilian market as it launches a joint venture with industry.

A gaggle of miniature robots are falling over themselves in a Japanese lab. But they are not malfunctioning: it is the way they have been designed to move.

The wheel-shaped robots, which are just 4 centimetres in diameter and 1 centimetre thick, were built by Shinichi Hirai and Yuuta Sugiyama at Ritsumeikan University in Kusatsu. The robots propel themselves along by continuously altering their shape.

Take something no wider than a human hair and shrink it a thousand fold to a few nanometers across, and its electronic and other properties change radically. But whether the crystal structure of these nanoparticles remains basically the same is a matter scientists continue to debate.

Now, a new report by scientists at the University of California, Berkeley, and Lawrence Berkeley National Laboratory (LBNL) shows that's far from the case.

Zinc sulfide nanoparticles a mere 10 atoms across have a disordered crystal structure that puts them under constant strain, increasing the stiffness of the particles and probably affecting other properties, such as strength and elasticity, according to the team's report.

"In this material, disorder and a kind of strain is pervasive throughout the whole particle," said Benjamin Gilbert, a postdoctoral fellow at UC Berkeley. "That is an important observation, because it emphasizes that the assumption of bulk structure is not good enough. We would expect to find this kind of behavior in a wide range of semiconducting materials."

Wouldn’t you like to be able to read off the screen of your laptop in direct sunlight? Your mobile phone battery to last much, much longer? Or your next flat screen TV to be less expensive, much flatter, and even flexible? Thanks to a breakthrough technology called Organic Displays, this could soon be reality.

Although the technology behind Organic LED (OLED) displays is pure chemistry, the applications are much more everyday - mobile telephone and television screens, laptop and stereo displays, car navigation systems, or even billboards.

Physical chemists in China have made carbon-50 molecules in the solid state for the first time. Lan-Sun Zheng and colleagues at Xiamen University, and co-workers at the Chinese Academy of Sciences in Beijing and Wuhan, prepared the molecules - which they describe as a long sought little sister of carbon-60 - in an arc-discharge technique involving chlorine. The result will allow scientists to study the properties of carbon-50 with a view to exploiting its unusual properties. The method developed by the Chinese team also opens the way to making other small, cage-like carbon molecules or "fullerenes" (S-Y Xie et al. 2004 Science 304 699).

Researchers from Meijo University in Japan and Research Centre Jülich in Germany have made what they say is the smallest stable carbon nanotube. The tube, just 3 Angstroms in diameter, grew inside a multiwalled carbon nanotube during a hydrogen arc discharge process.

“This breaks the theoretical limit of 4 Angstroms, and reaches their the tubes’ minimum structural limit,” Xinluo Zhao of Meijo University told nanotechweb.org. “The 3 Angstrom carbon nanotube has only four hexagons around its circumference and each end can be capped by half of a C12 cage (hexagonal prism) containing two tetragons.”

Liquid armor for Kevlar vests is one of the newest technologies being developed at the U.S. Army Research Laboratory to save Soldiers' lives.

This type of body armor is light and flexible, which allows soldiers to be more mobile and won't hinder an individual from running or aiming his or her weapon.

The key component of liquid armor is a shear thickening fluid. STF is composed of hard particles suspended in a liquid. The liquid, polyethylene glycol, is non-toxic, and can withstand a wide range of temperatures. Hard, nano-particles of silica are the other components of STF. This combination of flowable and hard components results in a material with unusual properties.

US researchers have made electronic circuits that can stretch like rubber. The flexible wires might create wearable electronics or artificial nerves that can bend inside the body.

Vigorous twisting and stretching destroys traditional electronics made from metals or silicon. And earlier versions of bendy electronics tended to break down if they were deformed too much.

Christopher Chen at Johns Hopkins University, Baltimore, and his co-workers built rubbery circuits out of several squashed but extendable gold wires. These are 20 times thinner than a human hair and wrapped in a springy polymer. The wires can be stretched by over half their initial length without loss of electrical conductivity.

Nanorings, a new type of geometry in the quest to build nanoscale devices, hold out near-term promise as injectable pressure sensors to monitor the human body.

The uniform, crystalline zinc-oxide rings, 1 to 4 microns in diameter and 30 nanometers thick, were produced by a research team at the Georgia Institute of Technology's Center for Nanoscience and Nanotechnology (Atlanta).

While the geometry simply joins nanowires and nanotubes in a line of building blocks for nanoscale devices, lead researcher Zhong Lin Wang called the piezoelectric nature of zinc-oxide "a dramatic advance." Wang believes a new class of nanoscale devices with applications in MEMS and biotechnology will result from the discovery.