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That Material is so Meta
I don’t like the idea of writing another negative post so soon, but this article just doesn’t seem right.
The idea here is that metamaterials, materials engineered to have specific optical properties, can be used to create a means of sticking two surfaces together. This is currently being researched by John Zhang ‘and buddies’ at the University of Southampton. According to one article, it is very similar to the way a gecko can climb on walls.
The explanation is that the metamaterial can stick to surfaces by using a specific type of force, the radiation pressure of light on surfaces. Light’s radiation pressure is a simple result of the photon side of its nature. It collides with a surface, imparting an absurdly small force on the surface. This force is nowhere near enough to mean anything in pretty much any situation.
Apparently through the use of resonance, it is possible not only to reverse the direction of the force, so that it pulls towards the surface instead of a push away, but it is also possible to make it strong enough to resist gravity. Of course, the amount of force needed to fight gravity changes based on how much is being carried. It might be enough for a needle-less push-pin, but not enough for a small robot. (Though I doubt it’d carry much of anything, especially when they say it needs borderline no energy to operate.)
My other main wonder is what geckos have to do with this in the first place. They certainly are cool, and can climb upside-down in a manner similar to what is being suggested here, but so can ants, and they aren’t getting any attention. The actual researchers don’t make any mention of them in the original article. The PopSci article, however, implies that they are actually the same type of force. Geckos cling to stuff via the use of a number of tiny hairs, or cilia, on their feet, not light energy. That would be downright inconvenient, seeing as geckos are commonly nocturnal.
Lastly, but easily most importantly, it seems that Zhang is coming out with this a bit too early. At the moment, they are relying purely on theory and speculation. They have yet to find any proof of their ideas. He expects this to be ‘easy to detect’ though. That phrasing kind of reminds me of this.
In a related (to the linked comic) note, it’s likely that the discrepancies in these articles are more a product of the article than the actual research. It could just be a strong case of this.
Scientists Make Ultra-Thin Invisibility Cloak
Until now, the invisibility cloaks put forward by scientists have been bulky devices — an obvious flaw for those interested in Harry Potter-style applications.
However, researchers at The Univ. of Texas at Austin have developed a cloak that is just micrometers thick and can hide 3D objects from microwaves in their natural environment, in all directions and from all of the observers’ positions.
Read more: http://www.laboratoryequipment.com/news/2013/03/scientists-make-ultra-thin-invisibility-cloak
Shapeshifting Metamaterial Could Revolutionize How We Treat Wounds
New Post has been published on http://www.todayheads.com/shapeshifting-metamaterial-could-revolutionize-how-we-treat-wounds/
Shapeshifting Metamaterial Could Revolutionize How We Treat Wounds
“When a drug can flow into a cavity then conform to the shape of the cavity and stay there, it offers unprecedented opportunities [in the] delivery of drugs.”
By Clay Dillow Posted 12.10.2012 at 10:00 am
Organic, Liquid-Like Hydrogel Made Of Chains Of Synthetic DNA Luo Lab
Researchers at Cornell University have somewhat accidentally created a strange new kind of metamaterial that flows like a liquid metal but also remembers its shape. In the presence of water, the liquid metamaterial snaps back into the form of its original container–a property that could have significant applications in treating wounds and beyond.
The material could be infused with drugs, then shaped to fit perfectly inside a wound. “When a drug can flow into a cavity as a liquid and then conform to the shape of the cavity and stay there as a solid (gel), it offers unprecedented opportunities [in the] delivery of drugs,” researcher Dan Luo says in an email.
The material is actually a hydrogel, one of those matrices of organic molecules that are filled with empty spaces. They are among the lightest materials we know of. Hydrogels have been touted as the next big thing on many frontiers, including drug-delivery schemes in which their extra real estate is used to hold pharmaceuticals that are released over time as the hydrogel dissolves.
In the presence of water, the liquid metamaterial snaps back into the form of its original container: Cornell University
The hydrogel created by the Cornell team is made of synthetic DNA–snippets of complementary coding that snap together to form complete strands just like the real, biologically created stuff. By coding them in certain ways, researchers can conjure different shapes and structures, and by mixing synthetic DNA with enzymes that catalyze self-replication, the Cornell team was able to get the material to extend itself into long chains, creating a bundle of DNA-based hydrogel.
The hydrogel flows like a liquid, but the team found that when they introduced it to water it returned to the the shape of the container in which it was originally formed, a kind of shape memory that was not part of its intended design. And they’re not exactly sure how it works. It could be the first organic metamaterial with “mechanical meta-properties.”
That’s intriguing on its own, but more tantalizing are the potential applications for a hydrogel with shape memory that can be triggered on demand. Such materials could be designed for very specific medical conditions, especially when blended with 3-D imaging technologies.
“After surgical removal of solid tumors, a key challenge is to kill the remaining cancerous cells that might spread afterwards,” Luo says. “A conforming gel after flowing into the cavity will have much more contact surfaces while at the time stay-put there. This will result in a more effective sustained release of drugs.”
But that’s not the only possible application. “In addition to the drug delivery, many more applications can be envisioned for different fields such as diagnostics, bio-separations and processings,” Luo says. “The potential will be significantly expanded when one thinks about combining other materials with our DNA metagel. Other materials can be gold nanoparticles, proteins, etc.”
It’s all kind of T-1000, but very, very interesting to think about.