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Posts mit dem Label Graphene werden angezeigt. Alle Posts anzeigen
Posts mit dem Label Graphene werden angezeigt. Alle Posts anzeigen

Montag, 23. Juni 2014

CAJ #13 - Last but not least

Graphene. It is an amazing material, one that will change the world and make us question everything we have known so far about science. Researchers around the globe are experimenting with graphene every day, always finding something new and exciting about it. Graphene opened up the doors for 2D materials, materials that up until now only excited in theory. The time of graphene and other 2D materials is yet to come and I hope that you are, as much as I am, anxious to see what it will bring us.

If you want to know more about graphene check out the following websites (I used them for my research too). Click on one of the following link and explore the world of graphene:



































45) http://www.understandingnano.com/graphene-chemical-sensor.html

46) http://www.understandingnano.com/graphene-applications.html

And last but not least, a TED Talk about graphene science: https://www.youtube.com/watch?v=eh3dA8xnZ4Y

I truly hope that you had fun while reading my CAJ, that you learned something new and are as thrilled as I am about graphene and its impact on us and our future.

XOXO A.



Sonntag, 22. Juni 2014

CAJ #12 - Ultrafiltration membranes

 As already mentioned in one of my earlier posts, the potential uses of graphene seem endless. It is hard to say where it should be applied first. However, in my opinion, we should invest more in the research of ultrafiltration membranes based on graphene.
Graphene possesses a number of qualities with regard to its interactions with water. Previous research showed that thin membranes made from graphene oxide laminates were impermeable to gases and vapours, except for water. New research is now testing the effectiveness of these membranes with regard to water filtration. Graphene could be used as a ultrafiltration medium that would act as a barrier between two substances.
What sets graphene apart from other similar membranes is that it is only one atom thick. A team of researchers at Columbia University has created a monolayer graphene filter with pore sizes as small as 5nm (nanometer). In comparison, other nanoporous membranes have pore sizes of 30-40nm. The membrane's ability to prevent salt passage depends on pore diameter. If the pores are too big, ions will be able to flow through it. If the pores are small enough, water will flow through while blocking out the ions. Because the pores in monolayer graphene filters are so small they can effectively filter NaCl (sodium chloride) salt from water.

Graphene is stronger and less brittle than aluminium oxide (currently used in sub-100nm filtration applications). These new types of membranes could be used in water filtration and desalination systems, as well as efficient and economically more viable biofuel creation. This would be a huge break through, especially the desalination system because all the water on Earth would become drinkable. This would help solve the problem of water shortage for many African countries. 


XOXO A.

Mittwoch, 18. Juni 2014

CAJ #11 - Other potential uses of graphene



1)      Sensors to diagnose diseases

Researchers have found out that graphene, strands of DNA and fluorescent molecules can be combined to diagnose diseases. The sensors are made by attaching fluorescent molecules to single strand DNA and then attaching the DNA to graphene. An identical single strand of DNA is combined with the strand on the graphene and a double strand DNA is formed. This double strand DNA floats off from the graphene and increases the fluorescence level. This process creates a sensor that can detect the same DNA for a particular disease in a sample.



2)      Bulletproof vests
Graphene could be applied in materials used in the production of bulletproof vests. Researchers from the University of Wollongong developed a new graphene-based material by combing equal parts of carbon nanotubes with graphene and adding them to the polymer. It has then been processed into fibers by using a wet-spinning method. This new material is stronger than spider silk and Kevlar that have so far been used to produce bulletproof vests. Bulletproof vests are made of layers of strong fibers that absorb the energy of the bullet, deform it, minimize the force of it and prevent the bullet from penetrating the vest. The research team working on this project said that the material is inexpensive and could be produced in large quantities.
3)      Gas sensors
The new gas sensors based on graphene could outperform today's leading gas sensors in detecting potentially dangerous and explosive chemicals, a study conducting at the Rensselaer Polytechnic Institute showed.  The sensors are made from continuous graphene nanosheets that grow into a foam-like structure about the size of a postage stamp. The flexible sensors measured ammonia and nitrogen dioxide at concentrations as small as 20 parts-per-million. This new discovery could be used by bomb squads, the police, various government agencies, as well as on airports.


4)      Condoms

Yes, you read right, I meant what I said. Graphene could be used in the production of condoms. Since graphene is highly stretchable, super thing, non-toxic and very strong it could be used to produce condoms that would not be able to be felt during intercourse. The idea is to mix graphene with latex in order to get a super thin and strong condom. These kinds of condoms would also act as an effective barrier to HIV and other sexually transmitted disease, more effective than condoms of this day and age can. This would be of great importance for the Third World where the birth rate is high and many people are infected by AIDS. One of the investors in condoms from graphene is the Bill and Melisa Gates Foundation that awarded scientists $100,000 for research.
XOXO A.



Sonntag, 15. Juni 2014

CAJ #10 - Who funds graphene research?

One of the biggest investors in graphene research is the European Union. Last year the European Commission invested €1bn to researchers to find a way to exploit graphene.

The funding will be distributed over a period of 10 years. It will go directly to the Graphene Flagship, led by Professor Jari Kinaret, from Sweden's Chalmers University in Gothenburg. The Graphene Flagship will co-ordinate 126 academic and industrial research groups across 17 countries. Their initial budget is €54m. The funding graphene received is part of Europe's Future and Emerging Technologies competition. Another project that received money from it is the Human Brain Project which focuses on developing a highly detailed model of the brain.

The research teams will be researching graphene and its properties in order to find a way to use it most efficiently and maybe even combine it with silicone. They hope that graphene will be applicable in the industry because it is an excellent electricity conductor, stronger than steel, harder than diamond, has ideal optical properties and is as thin as currently possible. The research areas that will be covered in the first 30 months include ICT communications, physical transport and applications of graphene in energy, technology and sensors. The Flagship will also try not to conduct research on topics where research has already been conducted. In one of the press reports that were released from the Flagship they said that their precise focus will be on graphene production.

The research group includes, among others, representatives from Nokia and Airbus which will provide management support and four Nobel laureates, namely Andre Geim and Kostya Novoselov, the two researchers who discovered graphene, as well as German physicist Klaus von Klitzing and French physicist Albert Fert.

Research is also being conducted at the University of Cambridge that has its own Graphene Centre. They want to go from theory to practice and enable graphene to be used in the industry as soon as possible. The Cambridge Graphene Centre alone attracted £13m in financial support from Nokia, Dyson, Plastic Logic, Philips and BaE systems, with an additional £11m from the European Research Council.
Visit the website of Graphene Flagship to find out how their research is going:
XOXO A. 

Sonntag, 8. Juni 2014

CAJ #7 - Potential use of graphene in solar cells

Solar cells are devices that convert the sun’s energy directly into electricity. They rely on the photoelectric effect - the ability of matter to emit electrons when a light is shone on it. Most of today’s solar cells are made out of silicon. However, silicon is very expensive because it is generally highly purified and then made into crystals that are sliced thin. Researchers have been trying to find an alternative that would be cheaper than silicon but have the same quality. Some believe the solution is inidium tin oxide, whereas others, namely MIT researchers, believe the answer is graphene. 

Silvija Gradček and eight other researchers at the  MIT, produced new graphene-based solar cells that are more flexible, lighter, and have a higher mechanical strength. The photovoltaic cell is based on sheets of flexible graphene coated with a layer of nanowires. This could lead to low-cost, transparent and flexible solar cells that could be set up on windows, roofs and other surfaces because of its low weight, mechanical strength and chemical robustness. This could potentially lead to the production of solar cells for households.
  

Graphene has a stable and inert structure, thus building a semiconducting nanostructure directly on its surface without damaging its electrical and structural properties has been a real challenge for researchers. They used a series of polymer coatings to modify its properties which allowed them to bond a layer of zinc oxide nanowires to it. Next they added an overlay of materials that respond to light waves. Throughout the whole process, graphene’s elemental properties remained intact.
1)  a flexible layer of graphene
2) a layer of polymer 
3) a layer of zinc-oxide nano wires (magenta color)
4) a layer of material that can extract energy from sunlight

The new graphene solar cells are not as efficient as certain types of silicon solar cells. Nonetheless, they are not far off the mark. Researchers will keep working on them in order to make them better and more efficient.  
So far the MIT research team has produced the graphene solar cell the size of only half an inch. It has not been proven yet that the technique can be used to create larger solar cells. Gradček says that it is only a matter of time when they will overcome this obstacle. She does not see that as a problem. Gradček claims that this technology could come on the market within the next couple of years. She hopes that this will make solar cells and solar power cheaper and available to the general public. 


XOXO A.

Dienstag, 3. Juni 2014

CAJ #6 - The potential use of graphene in the smart phone industry

We already know that graphene is the thinnest and lightest material in the world. It is almost entirely transparent and conducts heat and electricity better than silicon and copper. Thanks to this, it could revolutionize the smartphone industry. Many big companies are currently conducting research on how to use graphene to make smartphones thinner and flexible. It could also help develop wearable devices, such as smart watches and Internet-connected wristbands.

Samsung’s researchers discovered a method that would allow a single crystal of graphene, to retain its electrical and mechanical properties across a large area. They came to the conclusion that graphene’s electron mobility is 100 times greater than that of silicon. So far silicon has been the most widely used material in components that power many modern devices, such as smartphones, tablets and computers. By replacing silicon with graphene those components would become thinner and potentially allow super thin, transparent screens. Furthermore, graphene would deliver Internet to smartphones 100 times faster than the conventional way because it would convert light faster than the materials used in today’s existing smartphone components. This would make 3G and 4G a matter of history.



The application of graphene in technology would lead to the invention of wearable devices. Existing smart watches would be made lighter and added a screen, just as fitness bands. The future of these devices could look more like this: 




It is still unclear when graphene will find its way into our everyday technology and become available to the masses but Samsung researches are hoping to do it as soon as possible. Their goal is to bring phones that are completely bendable and foldable on the market by 2015. In January 2013 they officially launched their bendable OLED displays, calling them YOUM displays. In October 2013 they introduced the world’s first product to use a flexible OLED display – the Galaxy Round, a curved smartphone. This phone is similar to the Galaxy Note 3 but its display is flexible. If you follow this link you can watch Samsung’s YOUM flexible display demonstration https://www.youtube.com/watch?v=sJehexDPEsE .

YOUM flexible display

Samsung Round

XOXO A.

Samstag, 24. Mai 2014

CAJ #5 - Graphene abstract

The aim of this journal is to inform about graphene, one of the newest and most promising materials in the world. Graphene is the thinnest, lightest and most transparent material known to mankind. Its possibilities seem endless because of its many properties that are only exploited when graphene is combined with other materials, including gasses, metals, and sources of carbon. The methodology used for bringing forth the amazing possibilities of graphene includes reading various scientific papers and websites. Watching videos on YouTube that explain everything regarding graphene was also a very helpful tool in getting a better understanding of the true value and importance of graphene. Although graphene holds the solution to many problems, it is still in an early phase of research. The uses of graphene range from solar panels and smart phones to biological engineering and ultrafiltration. The price of graphene is linked to its quality, and not all applications require superb material quality. Mechanically exfoliated graphene comes in small, high-quality flakes that are incredible expensive, costing several thousand dollars per flake. The application of graphene in everyday appliances will therefore take some time. Graphene is bound to change our lives, to change the world we live in. Although it is currently facing certain problems, such as its cost, it still has a bright future ahead of itself because of it limitless application.

(227 words)


XOXO A.

Sonntag, 4. Mai 2014

CAJ #4 - Introducing graphene video

While googling my CAJ I came across really interesting uses of graphene that I would like to share with you. However, before I do so, we should repeat what we have learned so far. Since YouTube is a great source for visual learning I typed “graphene” into the search bar and looked for some videos that could help me and you to understand what graphene is all about and how it was discovered. Below is a really amazing video that explains in just two and a half minutes what I have written about so far. Take a look at it. You will not regret it, believe me. Even my brother liked it and that means something since he is usually not so interested in the things I do for university.




XOXO A.






Mittwoch, 30. April 2014

CAJ 3 - How was graphene discovered?


Phillip R. Wallace was the first to study graphene. In 1947 he studied graphene as a limiting case for theoretical work on graphite. The earliest TEM (transmission electron microscope) images of few-layer graphite were published by G. Ruess and F. Vogt in 1948.

Gordon Walter Semenoff, David P. DeVincenzo and Eugene J. Mele discovered in 1984 that the electric current could be theoretically carried by effectively massless charge carries in graphene.

S. Mouras is the first to mention the name graphene in 1987.

In 2004 graphene crystals were first isolated by two University of Manchester scientists, Andre Geim and Konstantin Novoselov.

(Andre Geim and Konstantin Novoselov)

Geim and Novoselov were trying to make graphite as thin as possible using lab equipment. They were struggling for months as they could not  make it thinner than 10,000 layers. After their work the lab surfaces were often covered in graphite and they would use scotch tape to clean it. Most of the time they would just look at the scotch tape to see what was happening to the graphite but would then throw in into the trash can. One day, instead of throwing it away, they decided to look at it under the microscope. They saw transparent pieces of graphite – graphene.


It is a true miracle that Geim and Novoselov continued their research on graphene because they wanted to give up on it since they overheard that other scientist at the university also use Scotch tape to clean graphite before putting it under the lens.

(a TEM image of the porous graphene)

The two scientists were first very surprised by their discovery because their physics intuition told them that this material should not exist since we live in a 3D world and graphene is a 2D material. However, they found a way of transferring the ultra-thin flakes of graphene from Scotch tape to a silicon wafer. After succeeding, they were able to examine the electrical properties of graphene.



Andre Geim and Kostya Novoselov were awarded the 2010 Nobel Prize in physics for their work and experiments regarding graphene. They continue to research graphene and other related two dimensional crystal materials.


The Nobel committee was not just blown away by the discovery the two scientist had made but also by the way they did it. The playfulness the two scientists showed while experimenting with graphite was the key to their success. “A playful idea is perfect to start things but then you need a really good scientific intuition that your playful experiment will lead to something, or it will stay as a joke for ever,” Novoselov says. Geim is known in the scientific community for his playful experiments. In 1997 he levitated a frog to demonstrate his work in magnetism.

XOXO A.


P.S. Many great discoveries that changed the world were accidental. It seems that sometimes the only thing standing in the way of a great discovery is a little bit of luck.

Isaac Newton was supposedly sitting in his garden when he discovered gravity. He saw an apple fall straight down from a tree. He wondered why they apple never falls upwards or off to a side. Newton soon discovered that all things fall straight down and that there is an attractive force pulling them down. Twenty years after that the published his theory of gravity.


In 1927 Fleming was experimenting with the properties of staphylococci. Before leaving his laboratory in August for holiday with his family, he had stacked all his cultures of staphylococci on a bench in a corner. After he returned, he noticed that one culture was contaminated with a fungus, and that the colonies of staphylococci immediately surrounding the fungus had been destroyed. Other staphylococci colonies farther away were normal. Fleming then grew the fungus in a pure culture and found that it produced a substance that killed a number of disease-causing bacteria. He identified the mold as being from the Penicillium genus, hence calling it penicillin. 


Dienstag, 22. April 2014

CAJ #2 - Difference between graphine and graphite

Graphene! What comes first to your mind? Did you, just like me, think that graphene is the material used in pencils? If you did, you were wrong. The central core of a pencil is called graphite. Graphite is a mineral that naturally occurs in metamorphic rock in different continents of the world. It contains two layers of carbon sheets and each layer contains very strong bonds. The layers of graphite are able to slide across each other. Graphite's abillity to conduct electricity and heat well makes it an outstanding material. Graphite can be found in pencils, batteries, brake linings, refractories and many other products.



Graphene is extracted from graphite. It is entirely composed of carbon atoms forming only one single layer of graphite. The two-dimensional crystal in only an atom thick. No material is thinner than an atom because if it were, it would not count as a material anymore. This means that graphene is one of the lightest and thinnest materials in the world. A square meter of graphene is a thousand times thinner than paper. Furthermore, graphene is one of the strongest materials known to mankind. It is about 200 times stronger but six times lighter than steel. A single sheet weighing only 0.77 milligrams can support a 4kg cat. Another astonishing property of graphene is that although it is only one atom thick, it is visible with the bare eye.

Graphene is almost entirely transparent. It is impermeable to gasses, even those as light as hydrogen or helium. Graphene is often called „the most diverse material known to mankind“ because of its many properties that are only exploited when graphene is combined with other materials, including gases, metals, and sources of carbon. Chemical components can be added to its surface to alter its properties. 

For a long time copper and silicon have been considered one of the best conductors of heat and electricity. However, the discovery of graphene showed otherwise. Graphene conducts electricty a thousand times better than copper. In comparison to silicon, graphene is better bacause it is highly flexible, not brittle and conducts electricity much more efficiently. 




XOXO A.

Mittwoch, 9. April 2014

#CAJ1 - Graphene and other super materials...

“Graphene and other super materials“ is my CAJ topic. The list we could choose from contained various interesting topics but I chose this one because I wanted to know more about graphene and how it could possibly change the world we live in. Before doing research I did not know much about graphene. I knew that it was one of the three naturally occurring allotropes of carbon, and thought that graphene is the material used in pencils. However, while doing research I discovered that graphene and graphite are two different things and are not to be confused. You will be able to find out more information about graphene and graphite in my blog posts. In the posts that are to follow I will also write general information about graphene, how it was discovered, how it could change the world, what green technology has to do with graphene and much more. I will also try to incorporate videos and pictures to help you visualize what I am writing about. No one can really predict how graphene will influence our future but it is sure that its possibilities are endless. I will not only focus on graphene but will also try to introduce you to other super materials such as stanene. I hope that you will learn something new by reading my blog posts and realize what a great and significant discovery graphene really is.  





XOXO A.