January 2012

A team of researchers led by Professor Sir Andre Geim demonstrated a graphene-Oxide based membrane that is impermeable to all gases and liquids (i.e. it's vacuum-tight) - but water can evaporate though it as if there's no membrane at all.

The researchers explain: "Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules. They arrange themselves in one molecule thick sheets of ice which slide along the graphene surface with practically no friction. If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules."

Researchers from Rice University and Rensselaer discovered that graphene is essentially invisible to water: when a single layer of graphene is used to cover silicon or most metals - there is almost no change in the water behavior when compared to a silicon without a graphene coating.

The researchers explain that "A drop of water sitting on a surface 'sees through' the graphene layers and conforms to the wetting forces dictated by the surface beneath. It’s quite an interesting phenomenon unseen in any other coatings and once again proves that graphene is really unique in many different ways".

Here's a guest article that Olan Dantes from Farnell sent us, regarding Graphene and Super Capacitors:

Electronic devices can become smaller and smaller to the point that it becomes invisible to the naked eye. But no matter what size they can have, they will still produce a lot of heat. The interconnecting wires as well as the multitude of transistors inside these devices at nano and micro scales are more than capable of creating heat spots. There could have been nothing wrong with the produced heat if it didn't induce damage.

Researchers from the University of Illinois and Dioxide Materials have showed that randomly stacked graphene flakes can make an effective chemical sensor. The flakes were fabricated by placing bulk graphite in a solution and bombarding it with ultrasonic waves that broke off thin sheets. This solution was filtered to produce a graphene film - made from stacked flakes. The flakes were used as the top layer of a chemical sensor. Movement of electrons through the film produced an electrical signal that flagged the presence of a test chemical.

According to the researchers, this new sensor is more reliable than existing sensors made from carbon nanotubes or graphene crystals. The researchers think that this is due to the fact that defects in the carbon-lattice structure near the edge of the graphene flakes allow electrons to easily "hop" through the film.

The University of Nottingham, UK, Polish Supramolecular Chemistry Network Foundation, and the Institute of Physical Chemistry of the Polish Academy of Sciences is organizing the Xth International Krutyn Summer School - focused on Carbon Nano-Materials science and technology. The organizers told us that there will be several speakers discussing Graphene related subjects.

The summer school will take place on June 19-25 in Krutyn, a village in Poland's Masurian Lake District.

Researchers from Rice University, together with colleagues in China, India, Japan and Texas, discovered a new one-step wet chemical process that turns carbon fiber into graphene quantum dots. The process enables making the GQDs in bulk - which are highly soluble.

The size of the QDs can be controlled via the temperature at which they're created. At 120 degrees they got a blue QD, at 100 a green one and a 80 degrees - a yellow QD.

Researchers from the University of Houston have used quantum mechanical calculations to show that graphene could be turned into a piezoelectric material by producing triangular-shaped holes in a specific pattern onto it and applying consistent pressure.

The team also says that the pseudo-piezoelectricity of graphene was as high as that of familiar piezoelectric materials such as quartz.

Researchers from the Rensselaer Polytechnic Institute have discovered new graphene based materials that can be customized to produce specific band gap and magnetic properties (i.e. have tunable functionality in electronics). The materials may be used to enable new nanoelectronics, optics, and spintronics devices.

The researchers found out that graphitic nanoribbons can be segmented into several different surface structures called nanowiggles. Each of these structures produces highly different magnetic and conductive properties. This means that you can basically create a new graphene nanostructure that is customized for a specific task or device.

A research team from Chalmers University of Technology in Sweden developed a new subharmonic graphene FET mixer at microwave frequencies. This could pave the way for new opportunities in future electronics as it enables compact circuit technology, potential to reach high frequencies and integration with silicon technology.

A mixer combines two (or more) electronic signals into one or two composite output signals. The ability in graphene to switch between hole or electon carrier transport via the field effect requires a unique niche for graphene for rf ic applications. The researchers say this symmetrical electrical characteristic has enabled them to build a G-FET subharmonic resistive mixer using only one transistor.

Andre Geim and Kostya Novoselov, the two Graphene researchers from Manchester University have been granted knighthoods. The two researchers won the 2010 Nobel physics prize for their groundbreaking graphene experiments.