Friday, January 27, 2012

Graphene: Another wondrous property revelation (GIZMAG)

Graphene reveals yet another extraordinary property

02:25 January 27, 2012

Ever since University of Manchester scientists Andre Geim and Konstantin Novoselov first isolated flakes of graphene in 2004 using that most high-tech pieces of equipment - adhesive tape - the one-atom sheet of carbon has continued to astound researchers with its remarkable properties. Now Professor Sir Andre Geim, (he's now not only a Nobel Prize winner but also a Knight Bachelor), has led a team that has added superpermeability with respect to water to graphene's ever lengthening list of extraordinary characteristics.
Graphene has already proven to be the thinnest known material in the universe, strongest material ever measured, the best-known conductor of heat and electricity, and the stiffest known material, while also the most ductile. But it seems the two-dimensional lattice of carbon atoms just can't stop showing off.
Stacking membranes of a chemical derivative of graphene called graphene oxide, which is a graphene sheet randomly covered with other molecules such as hydroxyl groups OH-, scientists at the University of Manchester created laminates that were hundreds of times thinner than a human hair but remained strong, flexible and were easy to handle.
When the team sealed a metal container using this film, they say that even the most sensitive equipment was unable to detect air or any other gas, including helium, leaking through. The team then tried the same thing with water and, to their surprise, found that it evaporated and diffused through the graphene-oxide membranes as if they weren't even there. The evaporation rate was the same whether the container was sealed or completely open.

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