Sci-Tech : Graphene: a novel material with myriad uses. After the discovery of one form of carbon — fullerenes — was awarded the Nobel Prize in Chemistry in 1996, this year's Nobel Prize for Physics was awarded to Andre K.
Geim and Konstantin S. Novoselov, both at the University of Manchester, U.K., for succeeding in producing, isolating, identifying and characterizing another form of carbon — graphene. Anyone who has used an ordinary pencil has probably produced graphene-like structures, but without knowing it. A pencil contains graphite, and when it is moved on a piece of paper, the graphite is cleaved into thin layers that end up on the paper and make up the text or drawing that we are trying to produce. A small fraction of these thin layers will contain only a few layers or even a single layer of graphite, i.e. graphene. Graphene, a single atomic layer of carbon, is the first two-dimensional (2D) crystalline material that has been identified and analyzed. It is a transparent conductor which is one atom thin. Different forms The discovery. Materials. A couple of stories about interesting, new materials caught my eye and I thought I might pass them along. The lightest solid In the picture above a 2.5kg brick is supported by 2gm worth of aerogel .
Aerogel, which is formed by a process somewhat similar to freeze-drying by removing the water from silica gel and replacing it with gas, in this case probably carbon dioxide, has been around since the 1930’s. It was first produced to settle a bet. The original version of the substance was too brittle to be useful for much but developments in its production have resulted in a product which is not only extremely light (1,000 times less dense than glass) but very strong and resistant to heat and cold. Applications that have been suggested include use as a building material which would be resistant to fire or blast, as armor, and for use in sporting equipment. Aerogel is also being tested for future bombproof housing and armour for military vehicles.
The thinnest solid. Graphene. High-quality graphene is strong, light, nearly transparent and an excellent conductor of heat and electricity.
Its interactions with other materials and with light and its inherently two-dimensional nature produce unique properties, such as the bipolar transistor effect, ballistic transport of charges and large quantum oscillations. At the time of its isolation in 2004, researchers studying carbon nanotubes were already familiar with graphene's composition, structure and properties, which had been calculated decades earlier.
The combination of familiarity, extraordinary properties, surprising ease of isolation and unexpectedly high quality of the obtained graphene enabled a rapid increase in graphene research. Andre Geim and Konstantin Novoselov at the University of Manchester won the Nobel Prize in Physics in 2010 "for groundbreaking experiments regarding the two-dimensional material graphene". Definition History The theory of graphene was first explored by P. Unzipping Carbon Nanotubes Can Make Graphene Ribbons. (PhysOrg.com) -- By "unzipping" carbon nanotubes, researchers have shown how to make flat graphene ribbons.
Graphene, which is a one-atom-thick sheet of carbon that looks like chicken wire, has unique electrical properties that could have many future electronics applications. However, one of the biggest challenges researchers currently face is producing graphene in large quantities. Recently, two research groups have demonstrated that unzipping carbon nanotubes can produce graphene ribbons in a variety of widths. In the first group, scientists at Rice University in Houston led by James Tour used sulphuric acid and an oxidizing agent to chemically create a hole in the carbon nanotubes.
The hole expanded along the side of the nanotube, unzipping the tube to form a flat graphene ribbon. The researchers suggest that this type of graphene ribbon could be used for conductive or semiconducting thin films, and possibly as an inexpensive substitute for monocrystalline silicon in photovoltaics. Graphene Outperforms Carbon Nanotubes for Creating Stronger, Mor. (PhysOrg.com) -- Three new studies from researchers at Rensselaer Polytechnic Institute illustrate why graphene should be the nanomaterial of choice to strengthen composite materials used in everything from wind turbines to aircraft wings.
Composites infused with graphene are stronger, stiffer, and less prone to failure than composites infused with carbon nanotubes or other nanoparticles, according to the studies. This means graphene, an atom-thick sheet of carbon atoms arranged like a nanoscale chain-link fence, could be a key enabler in the development of next-generation nanocomposite materials.
“I’ve been working in nanocomposites for 10 years, and graphene is the best one I’ve ever seen in terms of mechanical properties,” said Nikhil Koratkar, professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer, who led the studies. Epoxy materials infused with graphene exhibited far superior performance. The second advantage is surface area.