Graphene Oxide: Introduction and Market News - Page 36

Researchers from Nanyang Technological University in Singapore demonstrated how Indium and Indium chloride (InCl) can improve the process of reducing graphene oxide to graphene. The Indium helps by regenerating the sp2-conjugated system or selectively removing key oxygen-containing groups that could potentially decrease the performance of the graphene.

The researchers developed a method to apply the Indium, and they say that this method can be applied independently or in conjunction with other reducing agents to further improve the quality of chemically reduced graphene.

Back in October, researchers from India's VIT University started to study a new composite material made from graphene oxide and PVC. The GO was found to enhance the PVC to make it useful for battery electrodes, membranes and coatings.

The researchers continued to study the material, and they now published an article regarding the electrical characterization of the PVC-GO material as function of temperature. They say that according to their findings, the new material be very useful for all sorts of EMI applications, including radiation shields for radar and communication towers.

The University of Central Florida’s NanoScience Technology Center is developing graphene-based spray coating. The spray will be based on a polymer-graphene composite that will both be used to strengthen materials (used for the construction of aircrafts and cars) and to protect materials from corrosion.

The Center launched a program that will develop graphene oxide, the plastic host and a plasma spray. Garmor (which was spun off the UCF and licensed technology developed at the NanoScience Center) will assist with the formulation of the graphene oxide. The GO will need to be modified so it can be adhered to a plastic host and sprayed onto a surface while retaining its innate strength and elasticity.

Researchers from Korea developed a new skin cancer photothermal therapy using graphene oxide. The idea is to attach the GO particles to tumor cells, and then shine near-infrared laser light on them. The GO generate heat (and destroy the tumor cells) when exposed to the light, while healthy cells are not effected. Graphene is more efficient than gold for converting the light into heat, and it's also cheaper.

The researcher coupled the graphene with hyaluronic acid, a sugar polymer that is found naturally in skin and is an ingredient in skin care products. The polymer can penetrate the skin’s top layer, and tumor cells are known to express a large number of hyaluronic acid receptors on their surfaces. So this coupling allows the researchers to apply the graphene oxide particles to the skin, avoiding the need to inject them.

Resaerchers from Japan's National Institute for Materials Science (NIMS) developed a method to tune the band-gap of graphene oxide. The new method changes the bonding state of carbon atoms that compose graphene through reversible absorption and desorption of oxygen atoms on the graphene, and tuning the band-gap in situ.

The researchers say that this method enables band-gap tuning in a non-volatile manner - the tuned band-gap continues to exist even when voltage supply is stopped. To control the absorption and desorption of oxygen atoms on the graphene, the group used solid electrolytes in which hydrogen ions can move, thereby causing electrochemical reactions between oxygen atoms, which are chemically bonded to the graphene, and hydrogen ions.

Researchers from MIT and the University of California at Berkeley developed a new way to evenly functionalize graphene with oxygen at low (50-80 C) temperatures. The method is environmentally friendly (no harsh chemical treatment) and can be applied on a large scale.

The researchers use low-temperature annealing and this cause the oxygen atoms to form clusters. This leaves areas of pure-graphene between the oxygen clusters. This decreases the graphene's electrical resistance by four to five orders of magnitude (the oxygen clusters are insulating) which is good for applications such as sensing, electronics and catalysis.

Researchers from the University of Nebraska-Lincoln developed a new way to produce carbon nanofibers. The used crumpled graphene as a template followed by carbonization. They say their method promises to improve composite materials at a low cost because they do not need a lot of expensive nano materials.

The UNL team developed a process to incorporate graphene oxide nanoparticles as a template to guide the formation and orientation of continuous carbon nanofibers, which should improve the fiber's properties. That process involves crumpling the graphene in a way that improves graphene as a templating and orientation agent.

Back in May, Lomiko Metals, Stony Brook University (SBU) and Graphene Labs signed an agreement to investigate graphene based applications - mainly supercapacitors and batteries. Today the companies announced that they have reached a significant milestone by receiving a prototype graphene supercapacitor and a report from Stony Brook University and New York State’s Center for Advanced Sensor Technology (Sensor CAT).

The supercapacitor prototype was made using graphene composite material prepared using a proprietary technology developed at Graphene Labs. The measured specific capacitance of the prototype was found to be around 500 Farad per gram of the material. This value is comparable with the best values reported in the literature for a supercapacitor of this type.

Researchers from Nokia's Research Center in Cambridge developed a new humidity sensor based on graphene oxide. The researchers say that the new sensor is ultra fast (the fastest humidity sensor ever reported, in fact), thanks to the graphene 2D structure and its superpermeability to water molecules. The sensor Nokia developed is thin (15 nm), transparent and flexible.

The sensor's response and recovery time (the time to go from 10% to 90% of the high humidity value and vice versa) is less than 100 ms. The response rate is a function of the thickness of the GO, the thicker the film, the slower the sensor. Nokia has filed several patent applications regarding this work.

Localized hyperthermia is a solid tumor treatment that uses heat (above 43 degrees Celsius) to boost the cytotoxic effects of chemotherapy or radiotherapy and also increases the permeability of tumor cells to drugs. Graphene Oxide is a possible agent because it absorbs light in the near-infrared range.

Researchers from Portugal and Spain studied in vitro laser dosage and cell irradiation exposure time. It was discovered that cell culture temperature (after irradiating cells that had taken up graphene oxide) increases preferentially with laser power rather than with exposure time. Moreover, when the laser power is increased, cell necrosis leads to an increase of cytokine release to the surrounding medium.