Graphene has made significant advancements over this past week including it’s use in assembling a room temperature superconductor, near perfect electromagnetic shielding, spintronics and a new kind of algae-graphene composite that can form more durable Oceanic sensors.
As far as the super conductor is concerned, a team from Helmholtz-Zentrum Germany explain that by modulating the geometric assembly of particles you can control the area of space which is most conductive as well as to what degree it is conductive.
Graphene, being a metamaterial in some cases and a 2 dimensional material in others demonstrates unique emergent properties that only manifest when you shift the position of it’s atoms and molecules to assume a particular formation. This is similar to what you would expect from a Crystal. As far as the geometry itself is concerned, like a lot of other things that are extremely useful, including crystals – graphene is packed into a hexagon shaped latticework.
What scientists unveiled in this particular study is that rotating hexagonal layers of graphene by 1.1 degrees in relationship to one another for some reason, creates superconductivity at room temperature. That is a pretty significant breakthrough. Superconductivity has required extremely cold temperatures to function properly – in fact close to absolute zero, where atoms cease to vibrate completely. Even what they call high temperature superconductors still operate at -140 degrees Celsius.
Once you have room temperature superconductivity you can save millions of dollars you’d otherwise spend on maintaining cryogenic coolers. There are just much less complications to deal with in general, leading to a wider range of applications outside of what you can do inside of an expensive cryo chamber.
In particular, author’s elucidate the materials potential in composing lossless energy cables that will become more important as demand for renewable energy grows and high voltage transmission is required to counteract the intermittent temporality of solar, wind and geothermal energy.
In other news a team from the University of California Riverside has come up with a mix of graphene and epoxy resin that could protect us and our power grid from disruptive electromagnetic radiation. The new composite also dissipates excess thermal energy to avoid overheating. Which is particularly useful for combating high-energy radiation that will eventually destroy or degrade other materials over time.
A solar flare or electromagnetic pulse weapon could wipe out our power grid, resulting in a blackout. It is estimated that hundreds of millions of people would die as a result of a prolonged world-wide blackout. Aside from that, there are plenty of minor man-made and natural sources of electromagnetic radiation that could disrupt our own cardiovascular system and smaller electronic devices in a similar manner.
You see – everything communicates through electromagnetic radiation (another word for light), and there are plenty of healthy electromagnetic signals. In fact, they are required for your immune system to function properly. However, when electromagnetic activity becomes chaotically intense, disruption of local signals can lead to an abnormal reaction. So it’s good to know that this graphene composite can block up to 99.998% of electromagnetic signals.
According to the authors, in order to discover the new material they tested a bunch of bi-layer graphene with different levels of thickness. Eventually they zeroed in on the best option which offered both a thermal conductivity level 35 times greater than before while simultaneously providing defense from electromagnetic radiation in the x-band frequency range between a 8.2 gigahertz and 12.4 gigahertz
“As electronic devices become ever smaller and operate at higher and higher frequencies, they generate even more heat and electromagnetic waves. These not only degrade the devices themselves (EM waves also produce heat), but they can adversely affect neighboring electronics systems. EM radiation might also be dangerous for human and animal health and the environment.”
“…materials for thermal conductivity and electromagnetic shielding have very different characteristics, both types of material need to be employed in the same device, which adds to complexity and cost.”
Scientist from The Institute for solid state physics of the University of Tokyo and the University of California-Irvine have come up with a unique method of combining high thermal and electrical conductivity from graphene with the programmable magnetic spin of topological insulators, another state of matter entirely.
Topological insulators distinguish themselves from ordinary matter by demonstrating a set of peculiar electrical properties. For some reason the materials outer layer behaves like a conductor whereas the inner core acts more like an insulator. This creates what resembles a more easily accessible flat screen on the outside layer more suited for programming electrons by altering their magnetic spin with electromagnetic frequencies. The whole field of inquiry is a new and emerging method of information storage called spintronics and topological insulators are particularly suited for the task.
This particular state was achieved by sprinkling small amounts of bismuth and tellurium particles over top of the graphene. In order to confirm the subsequent transformation scientists controlled for external gate voltage, measuring both electrical conductivity and state density. Their research was published in the US Science magazine science advances on November 9th 2018
Derived from a combination of alginate from seaweed and graphene oxide nano-materials scientists have developed a new composite that can adapt to surroundings by altering its density and size. The new algae graphene Oxide composite was 3D printed using computerized systems that direct ultraviolet laser beams to carve a shape out of a photo-active polymer solution. In this case light from the laser beam actually bonds polymer compounds together creating a seamless object. The entire composite is built layer-by-layer as lasers trace a path around each blueprint.
“You could imagine a scenario where you can image living cells in a stiff environment and then immediately change to a softer environment to see how the same cells might respond,” Valentin said. That could be useful in studying how cancer cells or immune cells migrate through different organs throughout the body.
“These composite materials could be used as a sensor in the ocean that can keep taking readings during an oil spill, or as an antifouling coating that helps to keep ship hulls clean,” Wong said. The extra stiffness afforded by the graphene would make such materials or coatings far more durable than alginate alone.
This particular composite has potential for creating aquatic friendly oceanic sensors that can adapt to changes in oceanic current and to the oscillating presence of various chemical compounds that elicit a particular response by contracting or expanding the material. in so doing we could develop more accurate means of assessing climate change and the composition of the ocean as far as to what degree chemical pollution already exists and exactly how it changes based on weather patterns and the alteration of oceanic currents that precede