New research suggests that networks of single-walled carbon nanotubes printed onto bendable plastic perform well as semiconductors in integrated circuits. Researchers from the University of Illinois at Urbana-Champaign (UIUC) and Purdue University, whose work appears this week in Nature, say that these nanotube networks could replace organic semiconductors in applications such as flexible displays.

Development of flexible electronics has recently focused on organic molecules because, unlike silicon, they are compatible with bendable plastic substrates. Flexible electronics have potential in such applications as low-power electronic newspapers or PDAs that roll up into the size and shape of a pen. The problem with existing organic-electronic devices, however, is that "they aren't well developed for long-term reliability, and they perform far worse than silicon," says John A. Rogers, an engineering professor at UIUC and co-author of the Nature paper.

Carbon-nanotube networks, on the other hand, combine the performance of silicon with the flexibility of organic films on plastic. Rogers says that the speed of the nanotube device compares favorably with the speed of commercially used single-crystal silicon circuits. The transistors can also switch between on and off states in the range of several kilohertz, which is similar to the range of those used for liquid crystal displays and radio frequency identification (RFID) sensors. However, the on-off current ratio for carbon nanotubes is still a few orders of magnitude lower than that for silicon transistors.

The researchers made the networks by depositing nanotubes onto plastic by standard printing methods, which could lead to low-cost, large-scale fabrication. And the printed circuits can bend to a radius of about five millimeters without compromising the electrical performance of the device. "This method is good for flexible electronics that need to be printed over a large area," says Ali Javey, an assistant professor of electrical engineering at the University of California, Berkeley.

Using a technique called transfer printing, the researchers deposited randomly aligned carbon nanotubes onto a 50-micrometer-thick sheet of plastic, and then patterned gold electrodes and other circuit components onto the substrate. Because about one-third of the nanotubes in any network are metallic, which can short out the transistors, the researchers then etched narrow parallel lines through the network with soft lithography. By cutting the nanotubes, they can effectively eliminate the possibility of a purely metallic pathway connecting two electrodes while preserving the performance of the device.

Several challenges still remain before the nanotubes networks are ready for actual products. Devices need to be made in which the performance from device to device doesn't vary; billions of individual nanotubes have to be made with high purity and the right dimensions for optimal performance. The printing process also needs development, says George Gruner, a professor of physics at the University of California, Los Angeles. Gruner suggests that nanotubes could be dissolved into ink and then printed onto plastic. "These devices have to be cheap and disposable," especially for devices like RFID tags in food packaging, he adds.

Rogers's group's immediate goals are to work toward lower power and higher speed in the devices. "We want to push the limits to see how far we can go," he says.

via technologyreview 

A group of experts from around the world will hold a first of its kind conference Thursday on global catastrophic risks.

They will discuss what should be done to prevent these risks from becoming realities that could lead to the end of human life on Earth as we know it.

Speakers at the four-day event at Oxford University in Britain will talk about topics including nuclear terrorism and what to do if a large asteroid were to be on a collision course with our planet.

On the final day of the Global Catastrophic Risk Conference, experts will focus on what could be the unintended consequences of new technologies, such as superintelligent machines that, if ill-conceived, might cause the demise of Homo sapiens.

"Any entity which is radically smarter than human beings would also be very powerful," said Dr. Nick Bostrom, director of Oxford's Future of Humanity Institute, host of the symposium. "If we get something wrong, you could imagine the consequences would involve the extinction of the human species."

Bostrom is a philosopher and a leading thinker of transhumanism, a movement that advocates not only the study of the potential threats and promises that future technologies could pose to human life but also the ways in which emergent technologies could be used to make the very act of living better.

"We want to preserve the best of what it is to be human and maybe even amplify that," Bostrom said.

Transhumanists, according to Bostrom, anticipate an era in which biotechnology, molecular nanotechnologies, artificial intelligence and other new types of cognitive tools will be used to amplify our intellectual capacity, improve our physical capabilities and even enhance our emotional well-being.

The end result would be a new form of "posthuman" life with beings that possess qualities and skills so exceedingly advanced they no longer can be classified simply as humans.

"We will begin to use science and technology not just to manage the world around us but to manage our own human biology as well," Bostrom said. "The changes will be faster and more profound than the very, very slow changes that would occur over tens of thousands of years as a result of natural selection and biological evolution."

Bostrom declined to predict an exact time frame when this revolutionary biotechnological metamorphosis might occur. "Maybe it will take eight years or 200 years," he said. "It is very hard to predict."

Other experts are already getting ready for what they say could be a radical transformation of the human race in as little as two decades.

"This will happen faster than people realize," said Dr. Ray Kurzweil, an inventor and futurist who calculates technology trends using what he calls the law of accelerating returns, a mathematical concept that measures the exponential growth of technological evolution.

In the 1980s, Kurzweil predicted that a tiny handheld device would be invented early in the 21st century, allowing blind people to read documents from anywhere at anytime; this year, such a device was publicly unveiled. He also anticipated the explosive growth of the Internet in the 1990s.

Now, Kurzweil is predicting the arrival of something called the Singularity, which he defines in his book on the subject as "the culmination of the merger of our biological thinking and existence with our technology, resulting in a world that is still human but that transcends our biological roots."

"There will be no distinction, post-Singularity, between human and machine or between physical and virtual reality," he writes.

Singularity will approach at an accelerating rate as human-created technologies become exponentially smaller and increasingly powerful and as fields such as biology and medicine are understood more and more in terms of information processes that can be simulated with computers.

By the 2030s, Kurzweil said, humans will become more non-biological than biological, capable of uploading our minds onto the Internet, living in various virtual worlds and even avoiding aging and evading death.

In the 2040s, Kurzweil predicts that non-biological intelligence will be billions of times better than the biological intelligence humans have today, possibly rendering our present brains obsolete.

"Our brains are a million times slower than electronics," Kurzweil said. "We will increasingly become software entities if you go out enough decades."

This movement towards the merger of man and machine, according to Kurzweil, is already starting to happen and is most visible in the field of biotechnology.

As scientists gain deeper insights into the genetic processes that underlie life, they are able to effectively reprogram human biology through the development of new forms of gene therapies and medications capable of turning on or off enzymes and RNA interference, or gene silencing.

"Biology and health and medicine used to be hit or miss," Kurzweil sad. "It wasn't based on any coherent theory about how it works."

The emerging biotechnology revolution will lead to at least a thousand new drugs that could do anything from slow down the process of aging to reverse the onset of diseases, like heart disease and cancer, Kurzweil said.

By 2020, Kurzweil predicts a second revolution in the area of nanotechnology. According to his calculations, it is already showing signs of exponential growth as scientists begin to test first generation nanobots that can cure Type 1 diabetes in rats or heal spinal cord injuries in mice.

One scientist is developing something called a respirocyte, a robotic red blood cell that, if injected into the bloodstream, would allow humans to do an Olympic sprint for 15 minutes without taking a breath or sit at the bottom of a swimming pool for hours at a time.

Other researchers are developing nanoparticles that can locate tumors and one day even eradicate them.

And some Parkinson's patients now have pea-sized computers implanted in their brains that replace neurons destroyed by the disease; new software can be downloaded to the mini computers from outside the human body.

"Nanotechnology will not just be used to reprogram but to transcend biology and go beyond its limitations by merging with non-biological systems," Kurzweil said. "If we rebuild biological systems with nanotechnology, we can go beyond its limits."

The final revolution leading to the advent of Singularity will be the creation of artificial intelligence, or superintelligence, which, according to Kurzweil, could be capable of solving many of our biggest threats, like environmental destruction, poverty and disease.

"A more intelligent process will inherently outcompete one that is less intelligent, making intelligence the most powerful force in the universe," Kurzweil writes.

Yet the invention of so many high-powered technologies and the possibility of merging these new technologies with humans may pose both peril and promise for the future of mankind.

"I think there are grave dangers," Kurzweil said. "Technology has always been a double-edged sword."

via edition.cnn 

CIRCUS acts and movie special effects may never be the same again, if an idea for an invisible cable made of carbon nanotubes works out.

Being narrower than the wavelength of light, nanotubes are normally invisible - as long as they are separated by more than one wavelength. Now Nicola Pugno of the Polytechnic of Turin in Italy has calculated how many nanotubes would be needed to support a person, taking into account small defects that develop in the tubes during manufacture. When held 5 micrometres apart, to keep them invisible, they would form a cable only 1 centimetre in diameter weighing a mere 10 milligrams per kilometre (Microsystem Technologies, DOI: 10.1007/s00542-008-0653-9). A plate with more closely spaced holes could slide along the cable, bringing the nanotubes closer, and so into view.

via technology.newscientist 

Nanotech 'tissue' loves oil spills, hates water

A material with remarkable oil-absorbing properties has been developed by US researchers. It could help develop high-tech "towels" able to soak up oil spills at sea faster, protecting wildlife and human health.

Almost 200,000 tonnes of oil have been spilled at sea in accidents since the start of the decade, according to the International Tanker Owners Pollution Federation.

Clean-up methods have improved in recent years, but separating oil from thousands of gallons of water is still difficult and perhaps the biggest barrier to faster clean ups.

The new water-repellent material is based on manganese oxide nanowires and could provide a blueprint for a new generation of oil-spill cleaners. It is able to absorb up to 20 times its own weight in oil, without sucking up a drop of water.

Oil guzzler

Researchers led by Francesco Stellacci at the Massachusetts Institute of Technology in Cambridge, US, made membranes of tangled manganese oxide nanowires around 50 micrometres thick – about a quarter of the thickness of normal office paper.

The tiny wires are first suspended in liquid, before being strained out into flat sheets. "It's very similar to the process that makes paper," Stellacci says.

The manganese oxide nanowires are normally very attractive to water. However, adding a silicon coating switches the material to being strongly water repellent. It also becomes able to guzzle oil. Tests showed the material can suck up 20 times its weight in motor oil, and 10 times its weight in gasoline.

The new material is much more selective than other similar materials, such as those made of polymer or glass fibres, tests showed. Those materials all absorb some water as well as oil.

Heat proof

"Our material can be left in water a month or two, and when you take it out it's still dry," Stellacci says. "But if that water contains some hydrophobic [oily] contaminants they will get absorbed."

The membranes are tough, too, and can withstand being heated to evaporate off any oils. High temperatures remove the silicon coating, but once a new one is applied, the membrane is ready to use again, the researchers showed.

The membrane has "extraordinary selectivity and capacity for the separation of oil from water," says Joerg Lahann of the University of Michigan in Ann Arbor, US.

But Lahann points out that manganese oxide may not be the best material for real-world applications because it could be toxic. He says, though, that the new material "clearly provides a blueprint that can guide the design of future nanomaterials for environmental applications."

Journal reference: Nature Nanotechnology (DOI: 10.1038/nnano.2008.136)

Nanotechnology - Follow the emergence of a new technology in our continuously updated special report.

via technology 

Functionalized graphene sheets for polymer nanocomposites

T. Ramanathan¹, A. A. Abdala^2,7, S. Stankovich³, D. A. Dikin¹, M. Herrera-Alonso², R. D. Piner^1,6, D. H. Adamson⁴, H. C. Schniepp², X. Chen¹, R. S. Ruoff^1,6, S. T. Nguyen³, I. A. Aksay², R. K. Prud'Homme² & L. C. Brinson^1,5