Graphene Oxide

Graphene oxide's inherent defects provide a mechanical surprise

Scientists at Northwestern University have found how graphene oxide's inherent defects may present an interesting mechanical property. It seems that graphene oxide exhibits remarkable plastic deformation before breaking; While graphene is very strong, it can still break suddenly. It was found that graphene oxide, however, will deform first before eventually breaking.

The researchers used an experimentation and modeling approach to examine the mechanics of GO at the atomic level. Their discovery could potentially unlock the secret to successfully scaling up graphene oxide, an area that has been limited because its building blocks have not been well understood. 

High temperature reduction process increases thermal conductivity of rGO

A collaborative research performed by scientists from UC Riverside, Moldova State University, and Graphenea demonstrates that a method of reducing graphene oxide to graphene via a high-temperature treatment that increases thermal conductivity along the film direction, while decreasing it across the film. The scientists stress the potential of using this method for thermal management applications, such as fillers in thermal interface materials or flexible heat spreaders for cooling electronics. 

Heated rGO for thermal management applications

The research shows that thermal conductivity of GO can be majorly increased (nearly 30 times) by bringing GO to a high temperature during a reduction process. It appears that GO, when heated to 1000°C, turns to reduced GO (rGO) that has a high thermal conductivity along the sheet plane. In contrast, thermal conductivity perpendicular to the sheet shows an opposite trend, decreasing with thermal treatment.

Manchester University collaborates with Akzo Nobel to develop GO-based anti corrosion paints

Manchester University has teamed up with Amsterdam-based paints and coatings company Akzo Nobel, to investigate graphene oxide-based paints that provide protection against rust and corrosion for large metal structures, such as oil rigs, tankers and bridges.

This collaboration between Akzo Nobel and Manchester University is part of a €1m partnership in corrosion research. Akzo Nobel says graphene oxide could provide an ultra-strong, non-corrosive coating for a wide range of industrial applications. Corrosion in its various forms is estimated to cost the global economy $3 trillion a year. Products to protect against corrosion represent an $18 billion world market.

Graphene to enable color-tunable LEDs

Researchers from Tsinghua University in Beijing demonstrated a graphene-based LED that not only can be tuned to emit different colors of light, but can do so across nearly the entire visible spectrum: from blue (450-nm wavelength) to red (750-nm wavelength)—basically all colors but the darkest blues and violets. Such a color tunable LED has never before been realized.

Graphene to enable color-tunable LEDs image

The scientists made the light-emitting material from the interface of two different forms of graphene. These forms are graphene oxide (GO) and reduced graphene oxide (rGO). Placed at the interface of the GO and rGO is a special type of partially reduced GO that has optical, physical, and chemical properties that lie somewhere in between those of GO and rGO. The most important "blended" property of the interfacial layer is that it has a series of discrete energy levels, which ultimately allows for the emission of light at many different energies, or colors.

Graphene oxide-based composite helps create high-function thermistor

Researchers at VIT University, India demonstrated the application of conjugated polymer/Graphene oxide nanocomposite for thermistor applications. The study resulted in a thermistor that boasted excellent performance, suitable for electronics and sensors. A thermistor is a type of resistor whose resistance is dependent on temperature, more so than in standard resistors.

Interestingly, the study showed that lower amounts of graphene oxide (0.5, 1%) loading exhibited positive temperature coefficient, and higher loading (1.5, 2%) yielded negative temperature coefficient.

Graphene oxide "teabags" to remove mercury from water

Researchers at the University of Aveiro in Portugal designed unique "tea bags" using a porous graphene oxide foam, which they say can help purify water by removing dissolved mercury. These foams demonstrate several significant advantages over existing water purification systems: they are reusable, simple to synthesize and should be easy to produce in bulk at a relatively low cost. The scientists add that they are also not affected by pH, which is beneficial since other sorbents often need the pH to be optimized, which drives up costs. 

GO-infused ''teabags'' to clean water image

The scientists heated graphene oxide with ammonia to create a porous 3D material with a high surface area. After screening their materials for their ability to adsorb various toxic pollutants, the team chose to focus on mercury, one of the top three on the EU’s priority list of hazardous substances in water. The "tea bag" form was chosen due to the fact that the foam sometimes broke apart, and also to optimize contact with water. 

Japanese paper-cutting techniques may enable graphene-based flexible gadgets

A research team at the University of Michigan utilized Japanese paper cutting techniques, called kirigami, to create a new type of flexible conductor. The team believes that this technique may open up big possibilities for implantable medical devices, which have to flex and bend within the human body to work. Another option is gadgets that won't break when bending or flexing.

Japanese Paper-Cutting may enable flexible graphene-based gadgets

The first prototype of the kirigami stretchable conductor consisted of tracing paper covered in carbon nanotubes. The layout was quite simple, with cuts like rows of dashes. Later concepts were more intricate. for example, conductor sheets made out of graphene oxide, with etching cuts into the surface just a tenth of a millimeter long using laser beams and a plasma of oxygen ions and electrons.

Pages


Copyright 2009-2015 Metalgrass software