Graphene Oxide News
Back in May, Lomiko Metals, Stony Brook University (SBU) and Graphene Labs signed an agreement toinvestigate 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.
Archer Exploration and the University of Adelaide produced graphene products from medium-grade graphite
Archer Exploration, in collaboration with the University of Adelaide, has produced a wide number of graphene and intercalated graphite products from raw graphite, and from Campoona (Australia) medium-grade graphite concentrates.
Archer announced that University researchers managed to produce graphene oxide sheets, nanosheets, membranes, powders, films, and electrodes. Archers aims to produce high grade to ultra-pure natural flake graphite and manufacture high tech, high-value graphene products.
Reduced graphene oxide is a promising way to produce graphene materials, but currently used methods use harsh chemicals and are not environmentally friendly. A possible green method is photoreduction, but the dynamics behind this reduction aren't fully understood.
Now researchers from Germany's Max Planck Institute demonstrate and measure the ultrafast (picosecond) ultimate and fundamental time scale of graphene oxide photoreduction. The researchers explain that their research demonstrates the nature and fundamental timescale of GO reduction in water by UV irradiation.
Researchers from Korea's Gwangju Institute of Science and Technology in Korea developed high-performance supercapacitors based on graphene. They say these capacitors can store almost as much energy as a Li-Ion battery and can charge/discharge in seconds. They also last for many tens of thousands of charging cycles.
The researchers use a highly porous graphene that has a huge internal surface area. To fabricate this material they reduced graphene oxide with hydrazine in water agitated with ultrasound. This results in a graphene powder that they then packed into a cell shaped like a cell and dried it at 140 degrees Celsius under pressure for five hour. The material was used as an electrode.
Researchers from Korea's Incheon National University developed a new way to make conductive, flexible, and durable textiles (fabrics) wrapped with reduced graphene oxide (RGO). They report that those materials are useful to make conductive wires or functional fabrics in wearable electronics and more.
The main breakthrough is the choice of bovine serum albumin (BSA) - an amphiphilic protein that can be attached to organic and inorganic materials through hydrophobic and hydrophilic interactions - basically this is molecular "glue" that helps with graphene-oxide adsorption into any textile. The researchers fabricated those electrostatic self-assembly of BSA molecules onto all sorts of textiles (nylon yarns, cotton yarns, etc.) and then used a low-temperature chemical reduction.