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Tag: graphene

  • Your Next-Gen Condoms Could Be Made of Graphene

    This past May, the Bill & Melinda Gates Foundation lamented that the condom, one of the most simple tools ever devised to prevent the spread of sexually transmitted diseases and unwanted pregnancies, hasn’t really been improved upon in five decades. The condom we all know and love tolerate is in dire need of a tuneup.

    With that in mind, the Gates Foundation decided to issue a condom challenge. As part of round 11 of its “Grand Challenges Explorations” initiative, the charitable organization decided to award a series of grants to help scientists develop a better condom – one that “significantly preserves or enhances pleasure, in order to improve uptake and regular use.”

    Now, with the help of a $100,000 grant, scientists in the UK are working to develop a next-gen condom that’s thinner, stronger, and will hopefully provide people with a stronger incentive to wrap it up.

    And to achieve this goal, scientists at The University of Manchester are turning to graphene.

    Graphene, a one-atom thick layer of the mineral graphite, was first isolated in 2004 and is one of the strongest and lightest materials in the world. Its use in composite materials ranges from automobile construction to computer chips, and from Kevlar vests to smartphones. Soon, it may find a place in your condoms.

    These next-gen condoms would be made of a composite material, consisting of a mixture of graphene and latex or another sort of elastic poylmer.

    “This composite material will be tailored to enhance the natural sensation during intercourse while using a condom, which should encourage and promote condom use. This will be achieved by combining the strength of graphene with the elasticity of latex, to produce a new material which can be thinner, stronger, more stretchy, safer and, perhaps most importantly, more pleasurable,” says Dr. Aravind Vijayaraghavan, who heads the research at The University of Manchester’s new National Graphene Institute.

    Dr. Vijayaraghavan and his team are receiving one of a handful of grants just announced by The Gates Foundation to help increase and promote condom use around the world.

    “Quite simply, condoms save lives but new thinking is needed to ensure that men and women around the world are using them consistently and correctly to prevent unwanted pregnancies and sexually transmitted infections. These projects are working to improve uptake and regular use of male and female condoms by developing new condoms that significantly preserve or enhance pleasure and by developing better packaging or designs that are easier to properly use,” said the foundation in a release.

    Another interesting project now supported by The Gates Foundation is the Rapidom, a new condom applicator that supposedly provides a simple, one-motion application that should “minimize interruption.”

    But without a condom that people actually want to use, an applicator won’t get much use.

    “If this project is successful, we might have a use for graphene which will literally touch our every-day life in the most intimate way,” says Vijayaraghavan.

    Images via Shawn Latta, Flickr and National Graphene Institute at Manchester,

  • NASA Experiments With Nano-Sized Sensors

    NASA Experiments With Nano-Sized Sensors

    NASA is now working with a special material to develop nano-scale sensors that can detect trace elements in Earth’s upper atmosphere and find structural flaws in spacecraft.

    The material, called graphene, is just one atom thick and is composed of carbon atoms. It is 200 times as strong as steel, and is stable at extreme temperatures.

    “The cool thing about graphene is its properties,” said Jeff Stewart, the acting assistant chief for technology in the Mechanical Systems Division of NASA’s Goddard Space Flight Center. “It offers a plethora of possibilities. Frankly, we’re just getting started.”

    Stewart and his colleagues have developed a process to manufacture relatively large, high-quality samples of graphene. Using the material, the researchers are developing a miniature, low-mass, low-power detector that can measure the amount of atomic oxygen in the upper atmosphere. Graphene oxidizes when it absorbs atomic oxygen, creating a change in electrical resistance that can be measured. Such a device will be able to reveal the density of atomic oxygen at such heights, revealing its role in creating atmospheric drag.

    “We still don’t know the impact of atomic elements on spacecraft in creating a drag force,” said Fred Herrero, a retired Goddard researcher still working in an emeritus capacity. “We don’t know how much momentum is transferred between the atom and the spacecraft. This is important because engineers need to understand the impact to estimate the lifetime of a spacecraft and how long it will take before the spacecraft reenters Earth’s atmosphere.”

    NASA researchers now plan to fabricate and test the first generation of graphene-based chemical sensors by the end of the fiscal year.

    (Image courtesy NASA/Pat Izzo)

  • Using Pencil Lead for Microprocessors?

    Graphite, more commonly known as pencil lead, could become the next big thing in the quest for smaller and less power-hungry electronics.

    Resembling chicken wire on a nano scale, graphene – single sheets of graphite – is only one atom thick, making it the world’s thinnest material. Two million graphene sheets stacked up would not be as thick as a credit card. The tricky part physicists have yet to figure out how to control the flow of electrons through the material, a necessary prerequisite for putting it to work in any type of electronic circuit. Graphene behaves very different than silicon, the material currently used in semiconductors.

    We have reported on other uses of graphene here before, including better batteries and a better cooling system for electronics.

    Last year, a research team led by University of Arizona physicists cleared the first hurdle by identifying boron nitride, a structurally identical but non-conducting material, as a suitable mounting surface for single-atom sheets of graphene. The team also showed that in addition to providing mechanical support, boron nitride improves the electronic properties of graphene by smoothening out fluctuations in the electronic charges.

    Now the team found that boron nitride also influences how the electrons travel through the graphene. Published in Nature Physics, the results open up new ways of controlling the electron flow through graphene.

    “If you want to make a transistor for example, you need to be able to stop the flow of electrons,” said Brian LeRoy, an assistant professor in the University of Arizona’s department of physics. “But in graphene, the electrons just keep going. It’s difficult to stop them.”

    LeRoy said relativistic quantum mechanical effects that come into play at atomic scales cause electrons to behave in ways that go against our everyday experiences of how objects should behave.

    Take tennis balls, for example.

    “Normally, when you throw a tennis ball against a wall, it bounces back,” LeRoy said. “Now think of the electrons as tennis balls. With quantum mechanical effects, there is a chance the ball would go through and end up on the other side. In graphene, the ball goes through 100 percent of the time.”

    This strange behavior makes it difficult to control where electrons are going in graphene. However, as LeRoy’s group has now discovered, mounting graphene on boron nitride prevents some of the electrons from passing to the other side, a first step toward a more controlled electron flow.

    The group achieved this feat by placing graphene sheets onto boron nitride at certain angles, resulting in the hexagonal structures in both materials to overlap in such a way that secondary, larger hexagonal patterns are created. The researchers call this structure a superlattice.

    If the angle is just right, they found, a point is reached where almost no electrons go through.

    “You could say we created holes in the wall,” LeRoy said, “and as soon as the wall has holes in it, we find that some of the tennis balls no longer go through. It’s the opposite of what you would expect. That shows you how weird this is. It’s all due to those relativistic quantum effects.”

    The discovery puts the technology a bit closer to someday being able to actually control the flow of electrons through the graphene, the authors of the paper said.

    “The effect depends on the size of the hexagonal pattern resulting from the overlapping sheets,” explained Matthew Yankowitz, a first-year graduate student in LeRoy’s lab and the study’s lead author.

    The pattern, he explained, creates a periodic modulation of the potential – picture a ball rolling across an egg carton.

    “It’s a purely electronic effect brought about by the structure of the two materials and how they sit on top of each other,” Yankowitz said. “It’s similar to the Moiré pattern you see when someone wears a striped shirt on TV.”

    As of now, the researchers are not yet able to control how the graphene and boron nitride end up oriented relative to each other when they combine the two materials. Therefore, they make many samples and check the structure of each one under an electron microscope.

    “With our scanning tunneling microscope, we can get an image of each superlattice and measure its size,” Yankowitz said. “We take a picture and see what the pattern looks like. If the hexagonal pattern is too small, the samples are no good and we throw them out.”

    Yankowitz said about 10 to 20 percent of samples showed the desired effect.

    If it becomes possible to someday automate this process, graphene-based microelectronics might be well on their way to propel us from the silicon age to the graphene age.